GIFT   OF 

[PROF.  w.B.  RISING 


QUALITATIVE   ANALYSIS 


FOR 


SECONDARY   SCHOOLS 


BY 
CYRUS  W.  IRISH,  A.B.  (HARVARD) 

HEAD   MASTER   OF   LOWELL   HIGH   SCHOOL,    LOWELL,    MASS. 


NEW  YORK  •:•  CINCINNATI  •:•  CHICAGO 

AMERICAN    BOOK    COMPANY 


COPYRIGHT,  1899,  BY 
CYRUS  W.   IRISH. 


QUALITATIVE  ANALYSIS. 
W.    P.    I 


PREFACE 

MANY  teachers  of  chemistry  in  attempting  to  furnish  a  satis- 
factory course  in  Qualitative  Analysis  for  secondary  schools 
have  been  confronted  by  the  lack  of  a  text-book  sufficiently 
simple,  and  at  the  same  time  sufficiently  complete  for  their 
purpose.  The  many  excellent  text-books  on  Qualitative  Analy- 
sis already  published  have  been  specially  adapted  to  the  needs 
of  the  more  mature  college  student. 

This  work,  therefore,  has  been  made  as  simple  as  possible, 
while  providing  a  course  of  study  adequate  for  secondary 
schools.  Methods  of  basic  analysis  in  the  presence  of  phos- 
phates and  oxalates  have  been  omitted.  The  separation  of 
the  members  of  the  iron  group  has  been  greatly  shortened  and 
simplified  by  the  introduction  of  hydrogen  peroxide  to  oxidize 
the  chromium  to  the  acid  state.  Obscure  and  complicated 
reactions  have  been  omitted. 

The  first  half  of  a  one  year's  course  in  chemistry  should  be 
devoted  to  a  general  introduction  to  the  theory  of  the  science, 
and  to  a  close  study  of  the  most  common  nonmetallic  radicals. 
The  second  half  year  should  deal  with  the  basic  radicals  and 
should  be  combined  with  the  study  of  Qualitative  Analysis. 
If  descriptive  chemistry  of  the  basic  radicals  is  studied  by 
laboratory  methods,  the  metals  must  be  submitted  to  their 
more  important  reactions.  These  reactions,  well  studied,  equip 
the  student  for  intelligent  work  in  qualitative  separation  of  the 
metals.  The  subject  presented  in  this  way  always  holds  the 
interest  of  the  student  to  the  end,  and  the  stimulus  for  the  work 
is  always  found  in  the  fascination  of  the  subject.  Such  a  course 
as  here  outlined  gives  the  best  possible  training  in  inductive 
reasoning,  and  adds  as  much  to  the  general  information  of  the 
student  as  any  science  taught  in  secondary  schools. 

The  large  number  of  suggestive  questions  are  divided  into 
two  classes,  one  to  bring  out  the  conclusions  drawn  from  the 
experiments,  the  other  to  call  attention  to  the  metals  dealt 
with,  and  to  their  more  important  compounds. 

3 

237577 


^4.\  i :  PREFACE 

Wheu  the  student  has  performed  a  l<  preliminary  experi- 
ment," he  should  be  directed  to  write  the  name  of  the  chief 
product  formed  by  the  reaction  and  to  describe  its  general 
appearance,  in  his  notebook.  After  performing  a  series  of  pre- 
liminary experiments  the  student  should  complete  and  balance 
the  equations  representing  the  reactions. 

Descriptive  Chemistry  of  the  metals  to  be  separated  should 
be  studied  hand  in  hand  with  the  Qualitative  Analysis. 

A  careful  statement  of  each  step  of  the  analysis,  and  infer- 
ences drawn  in  the  laboratory  at  the  time  of  the  experiments, 
should  be  recorded  in  the  notebook.  In  the  case  of  the  known 
solutions,  the  teacher  should  mark  the  notebooks  for  neatness, 
order,  and  accuracy.  In  the  case  of  the  unknown  solutions, 
credit  should  be  given  for  neatness,  order,  accuracy  of  record, 
and  results  of  analysis.  It  is  highly  desirable  that  the  teacher 
should  question  each  individual  at  his  work  at  least  once  during 
each  laboratory  period,  and  give  the  student  credit  for  his 
knowledge  of  the  work.  This  method,  carefully  followed,  will 
prevent  a  mechanical  application  of  directions  on  the  part  of 
the  student. 

If  the  student  is  precipitating  Gr.  I  with  the  general  re- 
agent, for  instance,  the  line  of  questions  should  be  like  the 
following :  — 

Name  and  give  the  symbols  of  the  substances  that  may  be 
in  the  precipitate.  What  is  contained  in  the  filtrate  ?  How 
will  you  treat  the  filtrate  ?  What  is  the  solubility  of  the 
chlorides  of  this  group  in  H20  ?  Did  the  HC1  precipitate  all 
the  Pb?  If  not,  where  will  the  rest  of  the  Pb  be  found? 
What  kind  of  a  reagent  do  you  call  the  HC1,  "  general "  or 
"  special "  ?  What  is  your  next  step  with  this  precipitate  ? 
Why? 

The  author  wishes  to  acknowledge  his  great  indebtedness  to 
the  teaching  and  works  of  his  former  instructors,  Professor 
C.  L.  Jackson  and  Professor  H.  B.  Hill  of  Harvard  College. 

The  author  also  wishes  to  acknowledge  many  valuable  sug- 
gestions from  Miss  Helen  M.  Lambert  of  the  Lowell  High 
School. 


CONTENTS 

PART  PAGE 

I.     INTRODUCTION  —  DEFINITIONS,  METHODS  OF  NAMING    .  7 

Laboratory  Directions    .         .         .        -.         ...  12 

Abbreviations  used  in  the  Book    .         .         .         .         .  16 

II.     GROUPING  THE  BASES     ...                          .  17 

III.  BASIC  ANALYSIS 24 

Group  I 24 

Group  II,  Division  A 31 

Group  II,  Division  B     . 41 

Group  III       ....                  ....  48 

Group  IV 57 

Group  V         . 64 

Group  VI 71 

IV.  SYSTEMATIC  EXAMINATION  OF  SOLIDS  ....  80 

V.     ACID  ANALYSIS .88 

Group  I,  Division  A       .......  88 

Group  I,  Division  B                          .  89 
Group  II        ......                  .                  .91 

Group  III 93 

VI.     APPENDIX  —  PREPARATION  OF  SOLUTIONS               .         .  95 

Table  of  Solubilities .100 

5 


PART   I  — INTRODUCTION 


Definitions  and  Methods  of  Naming 

A  Radical  *  is  an  atom,  or  group  of  atoms  that  behaves 
like  a  single  atom.  Examples  :  H,  K,  Na,  Cu,  Pb,  simple 
radicals ;  NH4,  SO2,  NO2,  compound  radicals. 

A  Basic  Radical  is  a  metal,  or  any  radical  behaving  like 
a  metal.  Examples  :  Ag,  Cu,  Ca,  Na,  and  NH4 —  the  last 
so  classified  because  it  behaves  like  such  simple  radicals 
as  Na,  K,  and  Li. 

An  Acid  Radical  is  a  nonmetal,  or  any  radical  behaving 
like  a  nonmetal.  Examples  :  Cl,  Br,  I,  SO2,  NO2. 

An  Acid  is  a  substance  containing  H  that  may  be  re- 
placed by  a  basic  radical.  When  a  nonmetal  is  combined 
with  H  only,  as  in  HC1,  HBr,  H2S,  the  compound  is  said 
to  be  a  binary  (i.e.  composed  of  two  elements)  acid,  or 
an  hydracid.  When  the  nonmetal  is  combined  with  H 
and  O,  the  compound  is  called  a  ternary  (i.e.  composed  of 
three  or  more  elements)  acid,  or  an  oxyacid ;  and  the  char- 
acteristic name  of  the  acid  is  formed  by  adding  the  termi- 
nation -ic  to  the  name  of  the  nonmetal  to  denote  more 
oxygen,  or  the  termination  -ous  to  denote  less.  Exam- 
ples :  H2SO4  sulphuric,  and  H2SO3  sulphurous  acid. 

*  The  definitions  of  acids,  bases,  and  salts,  here  given,  are  based  on 
the  definitions  given  by  Professor  C.  L.  Jackson  in  his  course  in  Descrip- 
tive Chemistry  at  Harvard  College. 

7 


8  METHODS   OF   NAMING 

A  Salt  is  formed  from  an  acid  by  the  replacement  of 
all  or  part  of  its  H  by  a  basic  radical.  Examples  :  from 
HC1,  CaCl2,  NaCl,  NH4C1 ;  from  H2SO4,  Na2SO4,  CaSO4, 
(NH4)2SO4.  The  specific  name  of  the  salt  is  the  name 
of  the  basic  radical  changed  to  an  adjective.  If  the  salt 
is  formed  from  an  hydracid,  its  class  name  has  the  termi- 
nation -ide  ;  as,  calcic  chloride,  sodic  chloride,  and  am- 
monic  chloride  from  hydrochloric  acid.  If  the  salt  is 
formed  from  an  oxyacid,  the  class  name  of  the  salt  is 
formed  by  changing  the  -ic  termination  of  the  acid  to  -ate, 
and  the  -ous  to  -ite.  Examples :  from  H2SO4  sulphuric 
acid,  we  have  sodic  sulphate,  calcic  sulphate,  ammonic 
sulphate ;  from  H2SO3  sulphurous  acid,  we  have  sodic 
sulphite,  calcic  sulphite,  ammonic  sulphite.  Organic  acids 
frequently  have  other  H  atoms  besides  those  that  are 
replaceable,  such  as  HC2H3O2  acetic  acid,  in  which  only 
one  of  the  H  atoms  is  replaceable  by  a  basic  radical. 

An  Acid  Salt  is  a  salt  containing  H  that  may  be  re- 
placed by  a  basic  radical.  Thus,  from  H2SO4,  HNaSO4 
an  acid  salt,  and  Na2SO4  a  normal  salt. 

An  Hydroxide  is  formed  from  water  by  the  replacement 
of  one  half  its  H  by  a  radical.  Examples :  from  HOH 
water,  NaOH  sodic  hydroxide,  KOH  potassic  hydroxide. 
When  an  acid  radical  combines  with  H,  or  H  and  O,  an 
acid  is  formed ;  and  the  ternary  acids  may  be  regarded 
as  hydroxides. 

Examples  : 

from  HOH  water,  H  —  O  —  (NO2)  nitric  acid; 
from  2  HOH,  *     ~  Q~  (SO2)  sulphuric  acid. 

A  Base  or  Basic  Hydroxide  is  formed  from  water  by 
the  replacement  of  one  half  its  H  by  a  basic  radical. 


DEFINITIONS  9 

Examples:  from  HOH  water,  KOH  potassic  hydroxide, 
CaO2H2  calcic  hydroxide,  NH4OH  ammonic  hydroxide. 

The  term- "  base  "  is  frequently  used  in  a  general  way 
to  include  all  the  basic  radicals. 

When  a  basic  radical  combines  with  H  and  O,  a  base 
or  basic  hydroxide  is  formed.  A  base  will  neutralize  an 
acid  and  an  acid  a  base  to  form  a  salt.  When  a  base 
and  an  acid  are  brought  together,  a  salt  is  formed  with 
loss  of  one  or  more  molecules  of  water. 


HNO,  +  NaOH  =  NaNO,  +  HOH. 


NaOH  +  HC1  =  NaCl  +  HOH. 

s, .> 

QUERY.  To  produce  exact  neutralization  in  such  a 
case,  is  it  necessary  to  consider  the  weights  of  the  con- 
stituents used  ?  State  the  law  involved  in  your  answer. 

An  Alkali  is  a  base  soluble  in  water.  Examples : 
NaOH,  KOH,  NH4OH. 

The  Quantivalence  or  Valence  of  a  radical  is  the  num- 
ber of  H  atoms  that  it  can  combine  with  or  replace.  One 
atom  of  H  combines  with  one  of  Cl  in  HC1,  therefore  Cl 
is  univalent(r).  Two  atoms  of  H  combine  with  one  of  O 
in  H2O,  therefore  O  is  bivalent  (n).  Three  atoms  of  H 
combine  with  one  of  N  in  NH3,  therefore  N  is  trivalent  (m). 
A  Cu  atom  will  not  combine  with  H,  but  will  replace 
two  atoms  of  H  in  H2SO4  to  form  CuSO4,  therefore  Cu 
is  bivalent. 

The  terminations  -ous  and  -io  are  used  in  certain  cases 
with  the  first  or  specific  name  of  a  salt  to  distinguish 
between  two  salts  composed  of  the  same  elements  in 
different  proportions.  Examples  :  Hg2Cl2  mercurous  chlo- 
ride, HgCl2  mercuric  chloride,  FeSO4  ferrous  sulphate, 


10  DEFINITIONS 

Fe2(SO4)3  ferric  sulphate.  In  such  cases  as  these,  the 
termination  -ic  denotes  more  of  the  acid  radical,  and  -ous 
less. 

Qualitative  Analysis  is  the  method  of  detecting  the 
chemical  elements  and  their  compounds  by  studying  their 
properties. 

Quantitative  Analysis  is  the  method  of  determining  the 
quantity  of  such  elements  or  compounds. 

QUESTIONS 

1.  What  is  valence  or  quantivalence? 

2.  What  is  qualitative  analysis  V 

3.  What  is  quantitative  analysis? 

4.  Show  by  examples  the  difference  between  a  basic  and  an  acid 
radical. 

5.  What  is  a  base  or  basic  hydroxide  ?    Give  four  examples. 

6.  What  is  an  alkali  ?    Give  four  examples. 

7.  Give  examples  of  at  least  two  substances  that  are  not  alkalies 
in   constitution,   but   show  an  alkaline  reaction  with  litmus  paper. 
Can  you  suggest  a  reason  for  this  ? 

8.-  Name  a  salt  that  gives  an  acid  reaction  with  litmus  paper. 

9.   What  is  the  difference  between  an  acid  salt  and  a  normal  salt? 

10.  Relying  on  the  rules  for  naming  already  learned,  give  the 
correct  chemical   names  for  the  following  acids:    HC1,    IIBr,    III, 
HF,  H2S,  HN03,  HC2H302,  II2CO3,  ILPO4,  II3AsO4,  HC1O3,  II2S(>4, 
HNO2,  H2SO3,  HC1O2. 

11.  What  is  meant  by  basicity  of  an  acid? 

12.  Give  the  basicity  of  each  of  the  above  acids. 

13.  Replace  the  H  in  the  above  acids  by  the  following  basic  v«i  li- 
cals,  and  give  the  names  and  symbols  of  the  salts  formed : 

i        i        ii     in 
Ag,  NII4,  Ca,  Bi. 

14.  What  is  an  hydroxide  ? 

15.  What  is  meant  by  neutralization  ? 

16.  In  determining  the  chemical  names  from  the  symbols,  classify 
the  compound;  that  is,  determine  whether  it  is  an  acid,  a  base,  or 
a  salt,  etc.     If  the  substance  contains  both  a  metal  and  a  nonmetal 


SOLUTION  11 

(leaving  the  radical  OH,  which  always  indicates  an  hydroxide,  out 
of  consideration),  it  is  a  salt.  Notice  whether  it  is  a  binary  or  a  ter- 
nary compound.  If  binary,  suffix  the  termination  -ide  to  the  name 
of  the  acid  radical.  This  .name  is  now  preceded  by  the  name  of  the 
basic  radical  changed  to  the  adjective  form.  If  the  substance  is  a 
ternary  compound,  replace  the  metal  by  the  correct  number  of  H 
atoms,  to  show  the  acid  from  which  the  salt  is  theoretically  formed. 

Give  the  correct  chemical  names  for  the  following  compounds: 
FeSO4,  Fe2(SO4)3,  HNa2PO4,  HNaSO4,  NaOH,  KOH,  Ba(C9H3O2)2, 
Bi(N03)3,  As2S3,  Sb2S3,  Na2C03,  HNaCO3,  CaO2H2,.  (NH4)2S03, 
FeCl2,  Fe2Cl6,  Hg2Cl2,  HgCl2. 

Solution  and  Precipitation 

By  far  the  largest  portion  of  the  work  in  qualitative 
analysis  is  carried  on  in  what  is  known  as  the  wet  way ; 
that  is,  the  substance  to  be  examined  and  the  reagents 
used  are  in  solution,  usually  in  water,  or  if  in  any  other 
medium,  with  water  always  present.  As  a  rule,  water  must 
not  be  taken  into  consideration  in  writing  equations,  as 
it  does  not  undergo  a  chemical  change.  When,  however, 
the  water  is  decomposed  and  its  atoms  take  part  in  the 
general  rearrangement,  it  must,  of  course,  be  considered 
in  writing  the  equation. 

Solutions.  Of  greater  importance  than  any  other  one 
thing  in  qualitative  analysis,  is  a  knowledge  of  whether 
a  substance  is  soluble,  partly  soluble,  or  insoluble  in 
water;  and,  in  the  preliminary  tests  prescribed  in  this 
book,  the  question  of  solution  must  be  thoroughly  ex- 
amined by  the  student. 

A  solution  is  called  a  physical  solution  when  the  sub- 
stance undergoes  no  chemical  change,  but  is  so  finely 
diffused  through  the  solvent  that  it  cannot  be  seen  or 
separated  by  nitration,  though  it  can  be  recovered  by 
evaporation.  Example :  salt  or  sugar  in  water. 


12  PRECIPITATION 

A  Chemical  Solution  is  one  in  which  the  substance 
undergoes  a  chemical  change  and  the  new  substance 
formed  is  dissolved  in  the  menstruum.  A  substance  dis- 
solved in  this  way  cannot  be  recovered  by  simply  evapo- 
rating the  solvent.  If  copper  is  dissolved  in  nitric  acid, 
cupric  nitrate  is  formed  and  is  held  in  solution  by  the 
water  present. 

Precipitation.  Substances  that  are  in  solution  can  be 
separated  by  addition  of  such  a  reagent  as  will  form  a 
new  substance  that  is  insoluble  in  the  fluid.  This  process 
is  known  as  precipitation.  The  new  insoluble  substance 
is  a  solid  which  may  be  separated  from  soluble  substances 
by  nitration.  Knowledge  of  the  conditions  for  forming 
precipitates  of  the  various  elements  is  indispensable. 

Berthollet's  Law 

When  two  substances  can  form  a  substance  insoluble 
or  volatile  under  the  conditions  of  the  reaction,  that  in- 
soluble or  volatile  substance  will  be  formed  till  one  of 
the  factors  is  exhausted. 

LABORATORY  DIRECTIONS 

To  each  student  should  be  assigned  a  locker  in  which 
he  can  safely  keep  his  apparatus,  and  he  should  be  held 
strictly  responsible  for  all  breakage  and  loss. 

The  reagents  for  each  individual  should  include  the 
following : 

Dilute  H2S04,  HN03,  HC1. 

Concentrated  H2SO4,  HNO3,  HC1. 

HC2H302,  NH4OH,  NH4C1, 

(NH4)2C03,  (NH4)2S,  K2Cr04. 


LABORATORY   DIRECTIONS  13 

NOTE.  —  Yellow  ammonic  sulphide  is  a  mixture  of  ammonic  sul- 
phide (colorless)  and  the  higher  sulphides  of  varying  composition,  and 
is  sometimes  expressed  by  the  symbol  (NH4)2Sx.  For  the  sake  of 
simplicity  its  symbol  is  given  in  this  book  as  (NH4)2S  except  in  reac- 
tions (as  on  pages  33,  42)  in  which  it  evidently  furnishes  two  atoms 
of  S  for  the  reaction.  The  symbol  is  then  written  (NH4)2S2. 

The  three  acids  H2SO4,  HNO3,  and  HC1  are  always  to  be  used 
dilute  unless  otherwise  stated. 

The  other  reagents  may  be  conveniently  placed  on  a 
side  table,  and  should  include  the  following  : 

To  be  kept  in  Solid  Form  — 

Black  oxide  manganese,  Potassic  cyanide, 

Calcic  hydroxide,  Potassic  nitrate, 

Copper  foil,  Sodic  borate, 

Ferrous  sulphate,  Sodic  carbonate, 

Ferrous  sulphide,  Tartaric  acid, 

Iron  nails,  Zinc  strips. 
Potassic  chlorate, 

To  be  kept  in  Solution  — 

Alcohol,  Limewater, 

Ammonic  molybdate,  Magnesic  sulphate, 

Ammonic  oxalate,  Mercuric  chloride, 

Baric  chloride,  Mercurous  nitrate, 

Baric  hydroxide,  Potassic  ferricyanide, 

Bromine  water,  Potassic  ferrocyanide, 

Calcic  sulphate,  Potassic  sulphocyanide, 

Chlorine  water,  Silver  nitrate, 

Cobaltous  nitrate,  Sodic  chloride, 

Disodic  phosphate,  Sodic  hydroxide, 

Hydrogen  peroxide,  Stannous  chloride. 
Lead  acetate, 

(For  the  preparation  of  solutions  see  the  Appendix.) 


14  LABORATORY   DIRECTIONS 

Apparatus  necessary  for  Each  Student  : 

Eight  test  tubes,  6  in,  x  ^  in. 

One  test-tube  rack, 

One  filter  stand, 

Two  beakers, 

Two  filter  funnels, 

Two  evaporating  dishes, 

One  piece  of  platinum  foil,  1  in.  x  2  in.. 

One  platinum  wire,  3  inches, 

One  pair  steel  forceps, 

One  test-tube  holder, 

One  Bunsen  burner  or  alcohol  lamp, 

One  match  safe, 

One  blowpipe, 

One  iron  ring  stand, 

One  piece  of  iron  wire  gauze,  5  in.  x  o  in., 

One  asbestos  sheet,  6  in.  x  0  in., 

One  flask,  with  stopple,  glass  tubing,  rubber  tubing 
(3  inches)  for  making  wash  bottle, 

One  rat-tail  file,  and  one  three-cornered  file, 

One  test-tube  brush, 

Litmus  paper,  in  small  strips, 

One  package  of  filter  paper, 

One  glass  stirring  rod, 

One  bulb  tube. 

It  is  suggested  that  the  student  make  his  own  glass  rod 
by  closing  both  ends  of  a  glass  tube  about  8  inches  long ; 
and  his  bulb  tube  by  closing  one  end  of  such  a  tube  and 
blowing  gently  into  the  tube  till  the  end  is  blown  into  a 
bulb.  Also,  that  he  make  a  glass  spatula  by  closing  one 
end  of  a  glass  tube,  melting  the  other  end  in  the  flame, 
and  quickly  flattening  the  melted  end  by  pressing  it  with 
the  round  end  of  the  steel  forceps. 


TO   THE   STUDENT  15 

Laboratory  Directions  to  the  Student 

1.  You  are  responsible  for  the  good  order  and  neat- 
ness of  your  table  and  everything  belonging  thereto.     All 
your  apparatus  must  be  put  away  clean,  all  the  bottles 
put  in  their  proper  places  on  your  shelf,  and  the  table 
itself  left  clean  and  dry  at  the  close  of    each   period   of 
laboratory  work. 

2.  Provide  yourself  with  a  towel  and  also  with  a  large 
apron,   frock,  or   linen   duster  to  protect   your   clothing 
from  acids. 

3.  Under   no   circumstances    make   experiments   inde- 
pendent of  the  instructor's  directions.     If  you  wish  to 
perform  an  experiment  not  prescribed,  obtain  permission. 
If  you  do  such  work  on  your  own  responsibility,  remember 
that  the  dangers,  of  which  you  may  know  nothing,  are 
very  great. 

4.  In  case  of  accident,  notify  your  instructor  instantly, 
as,  in  the  case  of  burns  from  alkalies  and  acids,  remedies 
must  be  applied  at  once. 

For  Alkali  Burns,  apply  acetic  acid  diluted  with  water 
so  that  to  the  taste  it  is  about  one  fourth  as  sour  as 
vinegar.  This  solution  may  be  safely  applied  to  the  eye. 

For  Acid  Burns,  quickly  apply  dilute  solution  of  sodic 
carbonate,  then  wrap  in  vaseline. 

For  Ordinary  Burns,  apply  sodic  carbonate,  vaseline,  or 
hydrogen  peroxide. 

5.  All  solid  material  to  be  thrown  away  must  be  de- 
posited in  jars.     If  such  material  is  allowed  to  drop  into 
the  sink,  the  drainpipe  will  become  clogged.     The  water 
should  be  running  very  freely  into  the  sink,  before  throw- 
ing in  strong  acids. 

6.  When  using  reagent  bottles,  never  lay  the  stopple 
on  the  table,  but  hold  it  between  first  and  second  fingers 


16  ABBREVIATIONS 

while  using,  and  then  immediately  replace  the  bottle  on 
the  shelf. 

7.  Never  carry  reagent  bottles  from  the  side  table  to 
your  table,  but  use  them  at  the  side  table  and  return 
bottles  to  proper  place. 

8.  Never  put  matches  or  charcoal  in  drawers  or  lockers. 
Never  put  anything  but  your  regularly  assigned  appara- 
tus in  your  locker. 

Abbreviations 

The  following  abbreviations  and  signs  are  used  in  this 
book,  especially  in  the  tables  of  analysis : 

Pp.     =  precipitate  .  • .  =  therefore 

Fil.     =  filtrate  Res.  =  residue 

Gr.     =  group  Dil.  =  dilute 

Sol.     =  solution  Cone.  =  concentrated 

Orig.  =  original  Bx.  =  borax 

Pres.  =  present  +  =  plus 

Abs.   =  absent  x  =  unknown 

W.      =  white  c.c.  =  cubic  centimeter 

Pt.      =  part  C.P.  =  chemically  pure 


PART   II  — GROUPING   THE    BASES 


METHOD  OF  GROUPING  THE  BASES 

In  the  course  of  the  basic  analysis,  the  student  will 
learn  to  detect  twenty-seven  commonly  occurring  bases 
or  basic  radicals.  These  are  classified  in  six  different 
groups  in  accordance  with  certain  properties  which  permit 
a  group  precipitation  by  a  single  reagent.  A  reagent  used 
for  precipitation  of  a  whole  group  is  called  a  general  reagent. 
A  reagent  used  as  a  test  for  a  single  substance  is  known  as 
a  special  reagent. 

Experiments  showing  Method  of  Classification 

It  seems  hardly  advisable  for  the  student  to  spend  the 
time  required  to  discover  for  himself  the  best  method  of 
grouping,  by  an  exhaustive  study  of  all  the  elements.  If 
he  studies  with  care  the  characteristic  properties  of  one  or 
two  members  of  each  group,  it  should  be  sufficient. 

Use  the  following  solutions  :  AgNO3,  Cu(NO3)2,  AsCl3, 
Fe2Cl6,  Co(N03)2,  Ba(N03)2,  NaCl. 

Take  about  2  c.c.  of  each  solution,  and  add  HC1.* 

Points  to  be   Observed 
Whether  a  precipitate  is  formed. 

Whether  the  precipitate  is  soluble  in  an  excess  of  the 
reagent. 

*  Always  use  dilute  acids  unless  otherwise  directed. 

IR.   QUAL.   ANAL.  2  17 


18  GROUPING  THE   BASES 

The  color  of  each  precipitate. 

Whether  there  is  change  in  color  of  the  precipitate. 

Change  in  color  of  solutions. 

Chemical  equations. 

Tabulate  all  results  carefully  in  your  notebook,  accord- 
ing to  the  following  scheme  : 

HC1  was  added  to  the  seven  solutions  with  the  following 
results  : 

Typical  of  Gr.  I  AgNO3  +  HC1  =  AgCl  w.  pp.  +  I  IN ( )8. 
Typical  of  Gr.  II A  Cu(NO3)2  +  II Cl  =  No  change. 
Typical  of  Gr.  II  B  AsCl3  +  HC1  =  No  change. 
Typical  of  Gr.  Ill  Fe2Cl6  +  HC1  =  No  change. 
Typical  of  Gr.  IV  Co(NO3)2  +  IIC1  =  No  change. 
Typical  of  Gr.  V  Ba(NO3)2  +  HC1  =  No  change. 
Typical  of  Gr.  VI  NaCl  +  HC1  =  No  change. 

1.  Name   the   basic   radicals   that  are   represented    in 
these  solutions. 

2.  Can  HC1  be  used  to  precipitate  one  of  these  bases  ? 

3.  Under  what  conditions  ? 

4.  What  is  the  effect  of  HC1  on  some  of  these  solutions 
as  far  as  can  be  determined  by  your  senses  ? 

5.  Two  of  the  twenty-seven  bases,  Hg2  and  Pb,  behave 
like  Ag  under  the  above  conditions,   and  are  classified 
with  Ag  as  Gr.   I,  or  the  Silver  Group. 

6.  This  group  is  precipitated  as  what  class  of  salts  ? 

7.  Under  what  conditions  ? 

8.  What  is  the  general  reagent  for  Gr.  I  ? 


EXPERIMENTS  19 

Take  2  c.c.  of  each  of  the  same  .solutions  as  before. 
Make  the  AgNO3  acid  with  HNO3.  Make  the  others 
acid  with  a  few  drops  of  HC1.  Heat  all  the  solutions 
and  pass  bubbles  of  H2S  through  each  solution. 

AgNO3  +  H2S       = 
Cu(N03)2  +  H2S  = 
AsCl3  +  H2S 
Fe2CJ6  +  H2S 
Co(N08)a  +  H2S  = 
Ba(N03)2+H2S  = 
NaCl  +  H2S 

Determine  the  solubility  of  the  precipitates  in  (NH4)2S 
(yellow).  To  do  this,  filter  and  punch  hole  in  bottom  of 
filter,  wash  the  precipitate  through  into  test  tube  with 
(NH4)2S.  Pour  the  solution  in  the  test  tube  upon  the 
filter  and  repeat  until  the  precipitate  is  completely  re- 
moved. Then  heat  gently. 

1.  Which  of  the  bases  are  precipitated  by  H2S  in  acid 
solutions  ? 

2.  What  is  the  solubility  of  the  Cu  and  As  precipitates 
in  (NH4)2S  ? 

8.  The  following  bases  behave  like  Cu:  Hg,  Pb,  Bi,  Cd, 
and  are  classified  with  Cu  as  Gr.  II,  Div.  A,  or  the  Copper 
Group. 

4.  Sn  and  Sb  behave  like  As,  and  this  class  is  called 
Gr.  II,  Div.  B,  or  the  Arsenic  Group. 

5.  What  is  the  general  reagent  for  Gr.  II  ? 

6.  How  may  Div.  B  be  separated  from  Div.  A  ? 


20  GROUPING   THE   BASES 

To  the  same  solutions  as  before,  add  NH4OH. 

AgN03+NH4OH       = 
Cu(NO3)2  +  NH4OH  = 
AsCl3  +  NH4OH 
Fe2Cl6  +  NH4OH 
Co(N03)2  +  NH4OH  = 
Ba(N03)2  +  NH4OII  = 
NaCl  +  NH4OH 

To  the  same  solutions,  add  NH4C1  and  then  NH4OH. 

1.  Which  of  the  above  bases  are  precipitated  by  NH4OH  ? 

2.  When  NH4C1  is  previously  added,  is  the  effect  of 
NH4OH  modified  in  any  way  ? 

3.  The  bases  classified  with  Fea  are  Fe,  A12,  and  Cr2. 
and  these  four  bases  form  Gr.  Ill,  or  the  Iron  Group. 

To  the   same   solutions  as   before,   add   NH4OH   and 
(NH4)2S. 

AgN03  +  NH4OH  +(NH4)2S      - 
Cu(N03)2  +  NH4OH  +  (NH4)2s  = 
AsCl3  +  NH4OH+(NH4)2S 
FeaCl6  +  NH4OH  +(NH4)2S 
Co(N03)2+NH4OH+(NH4)2S  = 
Ba(N03)2  +  NH4OH  -h(NH4)2S  = 
NaCl  +  NH4OH  +(NH4)2S 

1 .  What  bases  not  already  precipitated  by  other  methods 
shown  in  these  experiments  are  precipitated  by  (NH4)2S 
in  the  presence  of  NH4OH  ? 

2.  Try  to  obtain  the  same  precipitates  by  making  the 
solutions  acid  and  adding  (NH4)2S. 


EXPERIMENTS  21 

3.  Co,  Ni,  Mn,  and  Zn  are  known  as  Gr.  IV,  or  the 
Cobalt  Group. 

4.  What  is  the  general  reagent  ? 

5.  Under  what  conditions  must  it  be  added  ? 

6.  What  class  of  salts  is  precipitated  by  it  ? 

To  the  same  solutions  as  before,  add  NH4OH  and 
(NH4)2C03. 

AgN03  +  NH4OH  +  (NH4)2C03       = 
Cu(N03)2  +  NH4OH  +(NH4)2C03  = 
AsCl3  +  NH4OH  +  (NH4)2CO3 
Fe2Cl6  +  NH4OH  +  (NH4)2CO3 
Co(N03)2  +  NH4OH  +  (NH4)2C03  = 
Ba(NOg)2+  NH4OH  +  (NH4)2CO3  = 
NaCl  +  NH4OH  +(NH4)2CO3 

1.  In  separating  the  groups  by  use  of  the  general  re- 
agents, the  first  group  must  be  removed  before  attempting 
to  precipitate  the  next.     Why  ? 

2.  Which  of  the  bases  are  precipitated  by  (NH4)2CO3  ? 

3.  Under  what  conditions  ? 

4.  Make  the  solutions  acid  and  attempt  to  obtain  the 
same  precipitates  with  (NH4)2CO3. 

5.  Gr.  V  includes  Ba,  Sr,  Ca,  and  Mg,  and  is  called 
the  Barium  Group. 

Na  has  not  been  precipitated  by  any  reagents  used  in 
these  experiments.  We  should  find  it  a  difficult  matter 
to  accomplish  with  any  reagent.  The  other  members  of 
Gr.  VI,  or  the  Sodium  Group,  K,  Li,  and  NH4,  possess 
the  same  peculiarity,  and  there  is  no  reagent  that  will 
precipitate  all  the  members  of  this  group  together. 


22  GROUPING   THE   BASES 

Perform  the  following  experiments  in  separations, 
making  use  of  the  knowledge  gained  in  the  foregoing 
experiments  : 

1.  Mix  2  c.c.  each  of  AgNO3  and  of  Cu(NO3)2  solu- 
tions.     Separate   by  precipitation    and   filtration.      How 
may  the  base  contained  in  the  filtrate  be  precipitated  ? 

2.  Mix  Cu(NO3)2  and  Ba(NO3)2  solutions.     Separate 
by  precipitation  and  filtration.     Also,  precipitate  the  base 
contained  in  the  filtrate. 

3.  Mix  Fe2Cl6  and  Co(NO3)2.     Separate  as  before. 

4.  Mix  Cu(NO3)2,  Co(NO3)2,  and  Ba(NO3)2.    Separate 
as  before. 

5.  Mix  AgNO3,  Cu(NO3)2,  Fe2(NO3)6,  Co(NO3)2,  and 
Ha(NO3)2.     Separate. 

6.  Mix  AsCl3  and  Ba(NO8)2.     Separate. 

In  what  form  was  the  Ag  precipitated  ?  Cu  ?  Fe  ? 
Co  ?  Ba  ?  As  ? 

The  methods  used  in  the  separation  of  the  above  elements 
represent  the  methods  of  separation  for  the  corresponding 
groups. 

Group  I  —  Silver  Group 

Hg2(-ous),  Ag,  Pb. 
Precipitated  by  HC1  as  chlorides  in  acid  solution. 

Group  II  —  Copper  and  Arsenic  Groups 

ii  ii       in      ii      n 

Div.  A.     Hg  (-ic),  (Pb),  Bi,  Cu,  Cd  (Copper  Group). 


in      in 


Div.  B.     Sn,  Sn,  Sb,  As  (Arsenic  Group). 
Both  divisions  of  this  group  are  precipitated  by  H2S  in 
acid  solutions. 


THE  GROUPS  23 

Sulphides  of  Div.  B  are  soluble  in  alkaline  sulphides, 
as  yellow  (NH4)2S,  while  the  sulphides  of  Div.  A  are 
insoluble. 

Group  III  —  Iron  Group 

II  VI  VI  VI 

(Fe),  Fe2,  A12,  O2. 

Chlorides  and  sulphides  are  soluble  in  acid  solutions. 
Members  of  this  group  are  precipitated  as  hydroxides 
in  alkaline  solutions  by  NH4OH. 

Group  IV  —  Cobalt  Group 

ii      it       ii       ii 
Co,  Ni,  Mn,  Zn. 

Chlorides  and  sulphides  are  soluble  in  acid  solutions. 
Hydroxides  are  not  precipitated  in  alkaline  solutions  in 
presence  of  NH4C1.  Members  of  this  group  are  separated 
as  sulphides  by  (NH4)2S  in  alkaline  solutions. 

Group  V  —  Barium  Group 

ii      ii      ii       ii 
Ba,  Sr,  Ca,  Mg. 

Precipitated  as  carbonates  from  alkaline  solutions  by 
(NH4)2C03. 

Group  VI  —  Sodium  Group 

Na,  K,  L'I,  NH4. 

This  group  is  not  precipitated  by  any  general  reagent. 
Its  members  are  detected  by  special  tests. 


PAET   III  — BASIC   ANALYSIS 


GROUP  I  —  SILVER  GROUP 


Precipitated  by  HC1  as  chlorides  in  acid  solution. 

Preliminary  Experiments 

Use  about  2  c.c.  of  any  given  solution  for  each  experi- 
ment. Keep  a  careful  and  systematic  record  of  results, 
and  whenever  a  change  occurs  on  addition  of  reagent,  ask 
yourself  the  question,  "  What  is  it  ?  " 

a 
Hg2  —  Mercury.     Mercurous  Compounds 

To  a  solution  of  Hg2(NO3)2  add  : 

1.  HC1  =  white  precipitate.     What  is  it  ? 

Filter,  make  hole  in  bottom  of  filter  with  glass  rod, 
wash  pp.  into  test  tube  by  directing  a  fine  stream 
of  water  from  wash  bottle  upon  the  pp.  Boil  the 
precipitate  with  H2O.  Is  it  soluble  ? 

2.  NaCl  or  any  other  soluble  chloride  = 
Filter  and  test  solubility  in  NH4OH. 

3.  H2S  = 

4.  Strip  of  Cu  foil,  remove  after  a  few  minutes  and  rub 

dry  = 

5.  NH4OH  = 

24 


GROUP  I  25 

Complete  and   balance  the  following,  underlining   all 
precipitates  : 


Hg2(N03)2 

Hg2(N03)2 

Hg2(N03)2+H2S 

Hg2Cl2  +  2  NH4OH        =  Hg2NH2Cl  +  NH4C1  +  2  H2O 

QUESTIONS 

On  experiments. 

1.  What  is  the  solubility  of  IIg2Cl2  in  H2O? 

2.  In  NH4OH  ? 

3.  In  dilute  acids? 

To  be  answered  by  reference  to  works  on  descriptive  chemistry. 

4.  What  is  calomel? 

5.  How  prepared? 

6.  For  what  used  ? 

7.  Derivation  of  the  name.  , 

i 
Ag  —  Silver 

To  any  solution  of  Ag,  as  AgNO3,  add  : 

1.  HC1  = 

a.  Filter  and  expose  a  portion  of  the  precipitate  to 

sunlight. 

b.  Reduce   another   portion   on   charcoal   in   blowpipe 

flame. 

2.  NaCl  = 

Filter  and  test  solubility  in  hot  H2O. 


26  BASIC   ANALYSIS 

3.  NH4C1  = 

Filter  and  add  NH4OH  to  pp.,  pouring  the  solution 
through  two  or  three  times  until  pp.  is  all  dis- 
solved. 

Now  add  HNO3  to  solution.  What  is  the  precipitate? 

Filter  and  expose  pp.  to  sunlight. 

4.  H2S  = 

5.  Any  soluble  chloride  = 

Complete  and  balance   the   following,  underlining  all 
precipitates  : 

AgN03  +  HC1  = 


AgCl  +  NH4OH  =  (NH3)3(AgCl)2  + 
(NH8)3(AgCl)2  +  HN03  = 
AgN03  +  H2S  = 

QUESTIONS 

1.  In  how  many  and  what  ways  can  you  precipitate  Ag  as  a 
chloride  ? 

2.  What  is  the  solubility  of  AgCl  in  H2O  ? 

3.  InNH4OH? 

4.  In  the  latter  case,  how  may  AgCl  be  veprecipitated? 

5.  What  is  the  effect  of  sunlight  on  AgCl? 

6.  What  use  is  made  of  this  fact  in  the  arts? 


7.  Where  is  Ag  found  in  nature? 

8.  In  what  forms  ? 

9.  What  is  lunar  caustic? 

10.  How  is  iron  plated  with  silver  ? 

11.  What  is  the  basis  of  indelible  ink? 

12.  Name  any  important  uses  of  Ag  and  Ag  compounds  that  you  can. 


GROUP  I  27 


II 


Pb  — Lead 

To  a  solution  of  Pb(NO3)2  or  Pb(C2H3O2)2  add: 

1.  HC1  = 

Filter  and  add  hot  H2O  to  pp.  until  it  disappears. 
Allow  to  cool.  Does  all  the  substance  crystallize 
out  ?  How  can  you  determine  this  ? 

2.  NaCl  or  any  other  soluble  chloride  = 

Filter  and  reduce  a  portion  on  charcoal.  To  the 
remaining  pp.  add  NH4OH.  Is  it  soluble  in 
NH4OH  ? 

3.  H2S=  5.    H2S04  = 

4.  (NH4)aS=  6.    K2Cr04  = 

Complete  and  balance  the  following,  underlining   all 

precipitates  : 

Pb(N03)2  +  HC1 

Pb(C2H3O2)2  +  NaCl 
Pb(NO3)2  +  NaCl 
Pb(N03)2  +  H2S 
Pb(C2H302)2+(NH4)2S  = 
Pb(N03)2  +  H2804 
Pb(NO3)2  +  K2Cr04 

QUESTIONS 

1.  What  is  the  solubility  of  PbCl2  in  cold  H2O? 

2.  In  hot  H2O  ? 

3.  InHCl?" 

4.  InNH4OH? 

5.  Name  and  describe  three  compounds  of  Pb  that  may  be  pre- 
cipitated to  prove  the  presence  of  Pb. 


6.  In  what  forms  is  Pb  found  in  nature? 

7.  Give  some  of  its  physical  properties. 


28  BASIC   ANALYSIS 

8.   Lead  pipes  are  much  used  for  water  pipes.    What  is  the  danger 
of  such  use  for  drinking  water? 

Air  and  water  together  dissolve  Pb  according  to  the  following 
reaction : 

Pb  +  O  +  H2O  =  FbO2H2. 

The  lead  hydroxide  thus  formed  is  slightly  soluble  in  water.  From 
this  source,  in  certain  classes  of  water,  there  is  danger  of  lead  poison- 
ing. Waters  containing  chlorides,  nitrates,  and  acid  carbonates  in 
solution  are  particularly  dangerous,  as  the  presence  of  these  com- 
pounds aids  the  solution  of  the  Pb.  Waters  containing  phosphates, 
sulphates,  and  sulphides  are  not  to  be  feared,  as  these  substances  form 
an  insoluble  film,  and  prevent  further  action. 

9.  How  may  the  presence  of  Pb  in  drinking  water  be  detected? 
For  this  purpose,  select  the  most  delicate  of  the  tests  for  Pb  that  you 
have  studied. 

10.  What  is  the  antidote  for  Pb  poisoning? 

11.  What  is  litharge? 

12.  Sugar  of  lead? 

13.  What  is  white  lead,  and  for  what  used  ? 

14.  What  is  chrome  yellow,  and  for  what  used  ? 


The  class  should  now  analyze  two  or  three  known 
solutions  of  this  group,  to  be  followed  by  two  or  three 
unknown  solutions,  according  to  the  following  directions 
for  analysis. 

Analysis.     Gr.  I 

To  the  original  solution  add  HC1.  A  white  precipitate 
formed  may  contain  Hg2Cl2,  AgCl,  PbCl2,  SbOCl,  and 
BiOCl.  Add  more  HC1,  and  the  last  two  substances  will 
redissolve  if  present.  The  filtrate  contains  Grs.  II-VI, 
and  is  marked  and  set  aside.  Wash  the  precipitate  with 
hot  H2O,  and  test  the  wash  water  with  H2SO4.  A  white 


GROUP  I 


29 


precipitate  of  PbSO4  shows  the  presence  of  Pb.  Con- 
tinue the  washing  with  hot  water  until  the  wash  water 
fails  to  give  any  further  precipitate  with  H2SO4.  NH4OH 
is  now  poured  on  the  HC1  precipitate  and  the  filtrate 
poured  on  two  or  three  times  to  insure  complete  solution  of 
the  AgCl.  A  black  residue  is  mercurous  amido-chloride, 
Hg2NH2Ci,  proving  the  presence  of  Hg2.  To  the  NH4OH 
nitrate  add  HNO3.  The  formation  of  a  white  precipitate 
of  AgCl  shows  the  presence  of  Ag. 

TABULATION,  GR  I 

Solution  contains  Grs.  I— VI.     Add  HC1  to  cold  solution. 


Pp.  Hg2Cl2  AgCl  PbOlj 

Wash  with  hot  H20  until  Pb  is  all  dissolved. 


Pp.  Hg2Cl2                     AgCl 
Wash  with  NH4OH. 

Filtrate  PbCl2 
Add  H2S04. 

Pp.  Hg2NH2Cl, 

black, 

Hg  ,  present. 

Fil.  AgCl  in  sol. 
Add  HN03. 

Pp.  white  PbS04, 
Pb  present. 

Pp.  white  AgCl, 
Ag  present. 

Fil.  = 
Grs.  II-VI. 


Notes  and  Suggestions 

Explanation  of  the  tabulation.  The  reagent  which  pro- 
duces the  precipitation,  or  separates  part  of  the  sub- 
stances in  the  form  of  solution  and  part  as  a  solid,  is 
always  underlined  thus:  |  .  Now  trace  the  long  line 
underneath  and  in  contact  with  [  to  the  left,  and  the 
symbols  of  all  precipitates  will  be  found.  At  the  first 


30  BASIC   ANALYSIS 

vertical  line  to  the  -right  of  these  symbols  will  be  found 
the  symbols  for  the  contents  of  the  filtrate,  thus : 

Reagent 

Precipitate  Filtrate 

Always  add  the  reagent  until  there  is  no  further  precipi- 
tate. Determine  this  point  by  adding  a  drop  of  the  re- 
agent to  the  filtrate. 

Avoid  excess  of  the  reagent,  as  it  will  finally  make  the 
solution  too  dilute  for  use  in  subsequent  operations. 

The  directions  are  given  with  the  assumption  that  all 
the  elements  are  present,  but  the  student  is  warned  to 
give  special  attention  to  all  negative  observations,  and 
correct  inferences  therefrom. 

PbCl2  is  slightly  soluble  even  in  cold  H2O.  Therefore, 
Pb  will  be  found  in  Gr.  II,  A,  when  it  is  present  in  Gr.  I. 
A  precipitate  may  be  formed  on  addition  of  HC1,  although 
no  member  of  Gr.  I  is  present,  but  will  dissolve  in  an 
excess  of  the  reagent.  This  would  be  due  to  the  presence 
of  Sb  or  Bi,  which  form  the  oxychlorides  in  water.  H2S 
and  (NH4)2S  give  the  most  delicate  reactions  for  Pb. 

A  Specimen  Page  from  Notebook 

When  a  solution  was  found  to  contain  Ag  and  Pb. 

Orig.  sol.  was  neutral  to  litmus  paper. 

Orig.  sol.  +  HC1  =  w.  pp.,  .-.  Hg2,  Ag,  and  Pb  may 
be  pres.  Fil.  =  Grs.  II-VI  and  is  set  aside.  Pp.  +  hot 
H2O.  Res.  Hg2Cl2  and  AgCl.  Fil.  +  H2SO4  =  w.  pp. 
PbSO4,  .*.  Pb  pres.  Res.  was  washed  with  hot  H2O 
until  wash  water  gave  no  further  pp.  with  H28O4.  Res. 
+  NH4OH  entirely  dissolved,  .-.  Hg2  abs.  Fil.  +  HNO3 
=  w.  pp.  AgCl,  . •.  Ag  pres. 

Found  in  solution,  Ag,  Pb. 


GROUP   II  — DIVISION    A  31 

\ 
GROUP  II,   DIVISION  A  — COPPER   GROUP 

ii  ii         in       ii        ii 

Hg(-ic),  (Pb),  Bi,  Cu,  Cd. 

Precipitated  by  H2S,  in  acid  solutions,  as  sulphides  in- 
soluble in  (NH4)2S  (yellow). 

Preliminary  Experiments 

ii 
Hg  —  Mercury.     Mercuric  Compounds 

To  a  solution  of  HgCl2  add  :  y 

1.  H2S  = 

a.  Filter  and  test  solubility  of  one  portion  in  (NH4)2S 

(yellow). 

b.  Test  solubility  of  second  portion  in  HC1. 

2.  (NH4)2S  = 

Filter  and  test  solubility  in  HNO3. 

3.  Cu  foil  = 

4.  SnCl2  = 

Complete   and  balance  the  following,  underlining   all 
precipitates  : 

HgCl2  +  H2S 

HgCl2  +  (NH4)2S  = 
HgCl2  +  SnCl2  .  = 
HgS  +  HN03 

QUESTIONS 

1.  What  is  the  solubility  of  HgS  in  HNO3? 

2.  InHCl?  3.   InH20?  4.   In  (NH4)2S? 
5.    Describe  three  tests  for  Hg. 


32  BASIC   ANALYSIS 

6.  Where  and  in  what  form  is  Hg  found  in  nature  ? 

7.  What  are  the  physical  properties  of  Hg  ? 

8.  What  are  some  of  its  uses  ? 

9.  What  is  amalgam  ? 

10.  What  is  vermilion  ? 

11.  Corrosive  sublimate  ? 

12.  What  was  the  celebrated  experiment  of  Priestley  in  which  he 
used  HgO? 

13.  What  is  fulminating  mercury? 

14.  What  is  the  antidote  for  Hg  poisoning? 

15.  Explain  the  use  of  the  terminations  -ous  and  -ic  in  naming 
Hg2Cl2  and  HgCl2. 

There  are  two  classes  of  mercury  compounds :  one  in 
which  the  double  atom  Hg2  is  bivalent,  and  another  in 
which  the  single  atom  Hg  is  bivalent.  In  the  first  case, 
the  two  atoms  are  supposed  to  be  united  with  each  other. 

Hg  -  Cl  -  Cl 

I  Hg 

Hg  -  Cl  -  Cl 

Mercurous  chloride  Mercuric  chloride 

The  termination  -ous  here  denotes  less  of  the  acid  radical 
(e.g.  Cl  above)  and  -ic  more. 

16.  Name  the  following  salts : 

Hg(N03)2,  Hg2(N03)2,  Hgl,,  Kg,!, 

in 

Bi  —  Bismuth 

To  a  solution  of  BiCl3  or  Bi(NO3)3  add  : 

1.    NH4OH  = 

Filter,  dissolve  pp.  in  a  few  drops  of  cone.  HC1,  and 
add  the  solution  to  a  large  quantity  of  H2O.  The 
oxychloride  of  bismuth  is  formed.  What  is  its 
symbol  ? 


GROUP  II— DIVISION   A  83 

2.  H2S  = 

Filter  and  determine  solubility  of  one  portion  of  pp. 
in  hot  HNO3,  and  of  a  second  portion  in  HC1. 

3.  (NH4)2S  in  excess  = 

To  (NH4)2S  add  HC1.     What  is  deposited  ? 

The  BiCl3  solution  contains  free  acid.  Can  you  explain 
what  occurred  at  first  in  reaction  No.  3  ?  Can  you  see  an 
objection  to  adding  (NH4)2S  to  an  acid  solution? 

Complete  and  balance  the  following,  underlining  all 
precipitates : 

BiCl3  +  NH4OH 

Bi(N03)3  +  NH4OH  = 
BiO3H3  +  HC1 
BiCl3  +  H20 
BiCl3  +  H2S 
Bi(N03)3  +  H2S 
(NH4)2S2*  +  HC1       = 

QUESTIONS 

1.  What  is  the  solubility  of  Bi2S3  in  HNO3? 

2.  In  (NH4)2S? 

3.  In  H20? 

4.  What  is  the  effect  of  H2O  on  BiCl3? 

5.  What  is  a  basic  salt  ? 

6.  What  is  the  symbol  for  the  basic  nitrate  or  subnitrate  of  bis- 
muth? 

7.  For  what  is  it  used  ? 

8.  How  does  Bi  occur  in  nature? 

9.  What  is  fusible  alloy  and  for  what  used  ? 

*  See  page  13,  note. 

IR.    QUAL.    ANAL.  3 


34  BASIC   ANALYSIS 

ii 
Cu  —  Copper 

To  a  solution  of  either  CuCl2,  Cu(NO3)2,  or  CuSO4  add  : 

1.  NH4OH  =  Salt  of  cupra-aniraonium 

2.  H2S  = 

a.  Filter  and  test  solubility  of  one  portion  in  HNO3. 

b.  Test    solubility    of    second    portion    in    (NH4)2S 

(yellow). 

3.  (NH4)2S  = 

a.  Filter  and  test  solubility  of  one  portion  in  HC1. 

b.  Test  solubility  of  second  portion  in  KCN.* 

4.  KCN  in  slight  excess  = 

5.  HC2H302  +  K4Fe(CN)6  = 

Complete   and   oalance  the  following,  underlining  all 
precipitates  : 

Cu(N08)2+NH4OH    =Cu(NH3)2(N03)2  + 

CuCl2  +  H2S 

CuS04+(NH4)2S 

Cu(NO3)2  +  KCN        =  Cu(CN)2  + 

Cu(CN)2  +  2  KCN       =  (KCN)2Cu(CN)2 

2  CuCl2  +  K4Fe(CN)6  =  Cu2Fe(CN)6  + 


*  Warning.  KCN  is  a  fatal  poison,  and  care  must  be  taken  that  it 
does  not  come  in  contact  with  abrasions  of  the  skin.  KCN  must  not 
be  added  to  an  acid  solution,  as  cyanogen  gas,  which  is  a  deadly  poison, 
may  be  liberated.  All  KCN  solutions  must  be  poured  into  the  sink  after 
using. 


GROUP  II  — DIVISION   A  35 

QUESTIONS 

1.  Describe  three  different  tests  for  Cu. 

2.  What  is  the  solubility  of  CuS  in  HC1  ? 

3.  InHNO3?        4.   In(NH4)2S?        5.   In  KCN? 

6.  Where  and  in  what  forms  is  Cu  found  in  nature  ? 

7.  Give  some  of  the  uses  of  Cu. 

8.  What  is  an  alloy ?  11.   Aluminum  bronze? 

9.  What  is  brass?  12.    What  is  blue  vitriol? 
10.  German  silver  ?  13.   What  is  verdigris  ? 

There  are  two  classes  of  Cu  compounds,  cuprous  and 
cupric,  as  in  the  case  of  mercury.  The  cupric  compounds 
are  the  more  important,  and  our  study  will  be  confined  to 
them. 

Cd  —  Cadmium 
To  a  solution  CdCl2,  CdSO4,  or  Cd(NO3)2  add  : 

1.  H2S  = 

Filter  and  pour  on  pp.  HNO3. 

2.  (NH4)2S  = 

Filter  and  pour  on  pp.  sol.  of  KCN. 

3.  KCN  in  slight  excess  = 

4.  NH4OH  = 

5.  NH4OH  in  excess  = 

Separation  of  Cd  from  Cu 

Mix  a  few  drops  of  CuSO4  and  CdSO4.  Add  NH4OH 
in  excess.  What  is  formed?  Add  a  solution  of  KCN 
with  constant  stirring  until  blue  color  just  disappears. 
Any  excess  of  KCN  must  be  avoided.  Now  pass  H2S 
through  the  solution.  A  yellow  precipitate  of  CdS  is 
formed.  CuS  is  not  precipitated  in  presence  of  KCN. 


36  BASIC   ANALYSIS 

Complete  and   balance   the  following,  underlining  all 
precipitates  : 

CdCl2  +  H2S 


>4  +  (NH4)2S  = 
Cd(NO3)2  +  NH4OH  = 
CdCl2  +  KCN 

QUESTIONS 

1.  What  is  the  solubility  of  CdS  in  H2O? 

2.  InHNO,?  3.   In  (NH4)2S?  4.   In  KCN? 

5.  In  what  form  is  Cd  found  in  nature  ? 

6.  Give  physical  properties  and  some  of  the  uses  of  the  metal. 

7.  Give  uses  of  any  of  the  salts  of  Cd. 

Analysis.     Gr.  II,  Div.  A 

Heat  the  filtrate  from  the  first  group  precipitate,  or  the 
solution  found  not  to  contain  Gr.  I,  acidulate  with  HC1, 
and  pass  H2S  through  for  some  time.  Filter  and  dilute 
the  filtrate  with  two  or  three  times  its  volume  of  H2O, 
heat,  and  pass  H2S  through.  Add  the  pp.  if  any  to  the 
original  pp.  Repeat  this  operation  until  the  precipitation 
is  complete.  The  filtrate  contains  Grs.  III-VI  and  is  set 
aside.  The  precipitate  is  HgS,  PbS,  Bi2S3,  CuS,  CdS,  SriS, 
SnS2,  Sb2S3,  Sb2S6,  As2S8,  and  As2S5.  Make  hole  in  filter, 
wash  precipitate  into  beaker,  and  heat  with  large  volume 
of  H2O.  Decant.  Repeat  three  or  four  times  and  filter. 
Reject  the  wash  water.  This  process  should  wash  out  all 
free  HC1.  Make  hole  in  filter  and  wash  the  precipitate 
into  a  test  tube  with  as  little  (NH4)2S  (yellow)  as  pos- 
sible. Pour  through  the  filter  several  times  to  remove  all 
adhering  precipitate.  Warm  gently  and  filter. 


GROUP  II  — DIVISION  A  37 

The  filtrate  contains  Gr.  II,  Div.  B,  Sn,  Sb,  and  As 
in  solution,  and  is  set  aside. 

The  precipitate  is  HgS,  PbS,  Bi2S3,  CuS,  and  CdS. 

Make  a  hole  in  the  filter  and  wash  pp.  into  beaker  with 
HNO3.  Heat  to  boiling.  All  but  HgS  will  be  dissolved. 
Frequently,  a  small  mass  of  S  with  adherent  particles 
forms  in  the  beaker  and  should  not  be  confounded  with 
HgS.  After  filtering,  dissolve  the  HgS  by  putting  a 
pinch  of  KC1O3*  on  the  precipitate  and  adding  cone. 
HC1.  Dilute  the  solution  with  H2O  and  add  SnCl2.  A 
white  or  gray  precipitate  of  Hg2Cl2  shows  Hg  present. 
An  alternative  method  is  the  addition  of  Cu  foil,  which 
will  be  coated  silver  white  with  Hg. 

The  HNO3  solution  is  now  partially  evaporated  with  a 
few  drops  of  H2SO4.  A  white  pp.  on  filtration  is  PbSO4. 
If  the  filtrate  now  contains  much  free  acid,  it  should  be 
evaporated  still  further.  Then  add  NH4OH  in  slight  ex- 
cess. The  precipitate  is  white  BiO3H3.  The  filtrate 
contains  Cu  and  Cd.  Wash  precipitate  and  add  two  or 
three  drops  of  cone.  HC1  and  allow  to  drop  into  a  large 
volume  of  H2O,  when  the  formation  of  white  BiOCl  con- 
firms the  presence  of  Bi.  If  the  NH4OH  filtrate  is  blue, 
it  shows  the  presence  of  Cu.  Make  an  additional  test  for 
Cu,  if  the  solution  is  not  blue,  by  acidifying  a  portion  of 
it  with  HC2H3O2  and  adding  K4Fe(CN)6,  when  a  brown 
precipitate  will  show  even  a  trace  of  Cu.  If  Cu  is  ab- 
sent, add  H2S  to  remaining  sol.  A  yellow  precipitate  of 
CdS  shows  Cd  present.  If  Cu  is  present,  cautiously  add 
a  solution  of  KCN  until  the  last  drop  causes  the  blue  color 
to  disappear  on  stirring,  and  add  H2S,  when  a  yellow 
precipitate  of  CdS  will  indicate  Cd. 

*  Warning.  KC103,  in  the  presence  of  H2S04,  is  dangerously  explosive. 
Take  care  that  all  solutions  used  with  KC103  are  free  from  H2SO4. 


38 


BASIC   ANALYSIS 


TABULATI 


Sol.  contains  Grs.   II-VI. 


Pp.     HgS  PbS  Bi2S3  CuS  CdS 

Wash  several  times  by  decantation. 


(SnS 

(NH4),S  ant 


Pp.     HgS  PbS  Bi2S3  CuS  CdS 

Make  hole  in  filter,  wash  into  beaker  with  HNO;i,  and  h 


Pp.     HgS,  black. 
Dissolve  in  cone.  HC1  and 
KC103  and  add 
SnCl2 

Fil.      Pb(N03)2           Bi(N03)3 
Partially  evaporate  with  a  fe^ 

Pp.  white  is 
PbS04  ; 
Pb  pres. 

Fil.      Bi(N03)3 
Add  NH 

White  or  gray  pp.  of  Hg2Cl2, 
Hg  pres. 
Or, 
Add  Cu  foil. 
Silver-colored  deposit  on 
foil  shows 
Hg  pres. 

Pp.     Bi03H3,  white, 
Bi  pres.     Confirm 
by  dissolving  in  2  or 
3  drops  of  cone.  HC1 
and  allowing  solution 
to  drop  into  large 
volume  H20.     White 
cloud  of  BiOCl, 
Bi  pres. 

GROUP  II  — DIVISION'  A 


39 


H.   II,   DIV.  A 


boiling  and  add  H.,S. 


Sb2S3         Sb2S5         As2S3 

(Div.  B,  Gr.  II) 
'ash  through  filter  with 


As2S5) 


Filtrate  =  Grs.    Ill- VI. 


riling. 


i(N03)2 
of  H2S04. 


i(N08),  ' 
light  excess. 


Cd(N03)2 


Cd(N03), 


Fil.  =  Gr.  II,  Div.  B. 

Sn,  'Sb,  and  As. , 


blue, 
u  pres. 

doubt,  test 
rtion  of  sol. 
HC,H302       . 
K4Fe(CN)6; 
n  pp., 
u  pres. 

If  Cu  is  abs.  add  H2S  to  remainder  of  sol. 

Pp.     yellow  CdS,      Cd  pres. 

If    Cu    is   present,    add    KCN    solution    until 
color  just  disappears,  and  then  H2S. 

blue 

| 

Pp.  .  yellow  CdS,      Cd  pres. 

40  BASIC   ANALYSIS 

Notes  and  Suggestions 

A  known  solution  containing  this  group  should  be 
worked  through  twice,  to  be  followed  by  unknown  solu- 
tions containing  some  of  the  members  of  Gr.  I  and  Gr.  II, 
Div.  A. 

Following  is  a  specimen  page  of  notebook  record  of  a 
solution  found  to  contain  Pb  and  Cd,  and  limited  to  Grs. 
I  and  II,  Div.  A : 

Sol.  was  neutral  to  litmus  paper. 

Sol.  -f  HC1  =  w.  pp.,  .-.  Hg2,  Ag,  and  Pb  may  be 
pres.  Fil.  =  Gr.  II,  Div.  A,  and  is  set  aside.  Pp.  + 
hot  H2O  entirely  dissolves,  .-.  Hg2  and  Ag  absent.  This 
solution  +  H2SO4  =  w.  pp.  of  PbSO4,  .-.  Pb  pres. 
Fil.  containing  Gr.  II,  Div.  A,  heated  and  H2S  added : 
yellow  pp.,  .-.  Gr.  II,  Div.  A,  pres.,  but  probably  limited 
to  Cd  and  trace  of  Pb  from  Gr.  I.  Filtrate  was  rejected. 
Pp.  was  washed  by  decantation.  Pp.  -f  HNO3  dis- 
solved entirely,  .-.  Hg  abs.  Partially  evaporated  with 
a  few  drops  H2SO4,  w.  pp.  PbSO4,  .-.  Pb  pres.  Fil.  -f 
NH4OH  in  excess,  no  pp.,  .-.  Bi  abs.  No  change  in 
color,  .-.  Cu  probably  abs.  Small  portion  of  sol.  acidified 
with  HC2H3O2  and  K4Fe(CN)6  added.  No  change, 
.-.  Cu  abs.  Remainder  of  sol.  +  H2S  gave  yellow  pp. 
ofCdS,  .-.  Cdpres. 

Solution  contains  Pb  and  Cd. 

It  will  be  noticed  that  the  directions  for  analysis  as- 
sume the  presence  of  all  the  elements  and  all  the  groups. 
The  student  must  not  conclude  from  this  that  he  must 
search  for  all  the  groups  when  the  solution  is  known  to 
be  limited  to  certain  groups.  When  the  addition  of  a 
reagent  shows  no  change,  a  correct  inference  from  this 


GROUP   II  — DIVISION   B  41 

negative  observation  may  greatly  shorten  the  work  of 
analysis.  Of  course  it  is  useless  to  go  through  the  analy- 
sis for  substances  already  proved  absent. 

QUESTIONS 

1.  What  is  the  general  reagent  for  Gr.  II,  Div.  A? 

2.  Give  the  names,  symbols,  and  colors  of  all  precipitates  pro- 
duced by  the  general  reagent  for  this  group. 

3.  What  is  the  reaction  of  HNO3  on  PbS? 

4.  OnCdS? 

5.  On  Bi2S3? 

6.  Reaction  of  HgCl2  on  SnCl2? 

7.  How  would  you  separate  Cu  from  Cd? 

8.  Hgfrom  Cu? 

9.  Bifrom  Cu? 
10.   Pbfrom  Cu? 

GROUP  II,  DIVISION  B  — ARSENIC   GROUP 

II  IV  III  III 

Sn,  Sn,  Sb,  As 

Precipitated   by  H2S,  in  acid   solutions,   as   sulphides 
soluble  in  (NH4)2S  (yellow). 

Preliminary  Experiments 

II          IV 

Sn,  Sn  —  Tin.     Stannous  and  Stannic  Compounds 

1.    To  a  solution  of  SnCl2,  add  H2S  = 

Filter,  make  hole  in  filter  paper,  and  wash  pp.  into 
test  tube  with  a  few  c.c.  (NH4)2S  (yellow),  and 
warm  gently.  Does  it  dissolve  ?  Treat  the  solu- 
tion with  HC1.  What  is  the  main  precipitate? 
Anything  else  ? 


42  BASIC    ANALYSIS 

2.  Boil  SnCl,2  with  cone.  HNO3.  This  converts  the  stan- 
nous  chloride  into  stannic  chloride.     To  the  SnCl4  thus 
produced,  add   H2S  =  ?     Filter  and  boil  pp.  with  cone. 
HC1  till  H2S  is  expelled.     Solution  now  contains  SnCl4. 
Dilute   slightly,    add   iron   nail,  and    warm    for   a   short 
time.      The    SnCl4   is   reduced   to    SnCl2.       Decant   into 
another  test  tube  and  add   HgCl2.      The  precipitate  is 
Hg2Cl2. 

3.  Make  a  little  SnS  and  test  solubility  of  one  portion 
in    (NH4)2CO3.      Test   solubility   of   second   portion   in 
(NH4)2S  (yellow). 

4.  Add  a  little  HC1  to  SnCl2  in  beaker  and  put  in 
a  small  battery  made  by  placing  Ft  foil  and  Zn  in  con- 
tact.    When  all  action  ceases,  remove  the  Ft  foil,  and  wash 
the  foil  in  warm  H2O  and  HC1.     The  Sn  will  dissolve  from 
the  Ft  as   SnCl2.      Four   off   solution   and  add   HgCl2. 
What  is  the  precipitate  ? 

5.  To  SnCl2  add  HgCl2  = 

6.  To  SnCl2  add  HgCl2  in  slight  excess  = 

Complete  and  balance  the   following,    underlining  all 
precipitates  : 

SnCl2  +  H2S  = 

SnCl4  +  H2S  = 

SnS  +  (NH4)2S2*  =  (NH4)2SnS3 

(NH4)2SnS3  +  2  HC1  =  SnS2  +  2  NH4Cl  +  H2S 

Sn  +  HC1  = 

SnCl2  +  HgCl2  =  Hg2Cl2  + 

SnCl2  +  Hg2Cl2  =  2Hg  + 

*  See  page  13,  note. 


GROUP  II— DIVISION  B  43 


QUESTIONS 

1.  What  is  the  solubility  of  SnS  in  (NH4)2S  (yellow)? 

2.  How  does  the  iron  nail  affect  the  SnCl4  on  boiling  ?    Explain 
fully. 

3.  What  is  reduction  ? 

When  an  element  has  two  degrees  of  quantivalence,  reduction 
changes  it  to  the  lower  degree,  while  oxidation  changes  it  to  the 
higher  degree  of  quantivalence. 

4.  Describe  two  tests  for  Sn. 


5.  Where  and  in  what  form  is  Sn  found  in  nature? 

6.  State  some  of  its  uses. 

7.  What  is  bronze  ? 

8.  Britannia  metal  ? 

9.  Pewter? 

10.    Name  one  use  for  SnCl2. 

in 

Sb  —  Antimony.     Antimonious  Compounds 

Use  a  solution  of  SbCl3,  or  SbOKC4H4O6  tartar  emetic. 
The  latter  can  be  used  in  cases  where  a  dilute  solution 
without  free  acid  is  desired,  as  it  is  the  only  soluble  anti- 
monious  salt  that  is  not  decomposed  by  H2O. 

1.  Add  H2S  to  SbCl.  = 

it  O 

2.  Add  H2S  to  tartar  emetic  = 

Filter  and  dissolve  precipitate  in  (NH4)2S  (yellow). 
Treat  the  solution  with  HC1.  What  is  the  pre- 
cipitate ?  Anything  else  ?  Filter.  Throw  on 
precipitate  a  pinch  of  KC1O3  and  add  cone.  HC1. 
Dilute  the  solution  with  H2O  and  put  in  the  Pt  and 
Zn  battery.  A  black  stain,  on  the  Pt  foil  indi- 
cates the  presence  of  Sb.  Dissolve  this  stain  in 
tartaric  acid  and  a  few  drops  HNO3,  and  add  H2S. 


44  BASIC   ANALYSIS 

3.  Add  H2S  to  SbClg  = 

Determine  if  careful  dilution  with  H2O  will  aid  the 
precipitation.  Filter  aoid  test  solubility  of  one  portion 
in  (NH4)2CO3  and  second  portion  in  (NH4)2S  (yellow). 

4.  Add  H2O  to  SbClg  = 

Complete  and  balance  the  following,  underlining  all 
precipitates  : 

SbClg  +  H2S  = 

SbClg  +  H20  = 

Sb2S3  +  3(NH4)2S2  =  2(NH4)3SbS4  +  S 

2(NH4)3SbS4  +  6  HC1  =  Sb2S6  +  6  NH4C1  +  3  H2S 

QUESTIONS 

1.  What  is  the  solubility  of  Sb2S3  in  (NH4)2S  (yellow)? 

2.  In  (NH4)2C03? 

3.  Describe  two  tests  for  Sb. 

4.  How  does  Sb  occur  in  nature  ? 

5.  What  are  some  of  its  uses? 

6.  Give  uses  of  one  of  its  compounds. 

As  —  Arsenic.     Arsenious  Compounds 

As  behaves  both  as  a  basic  and  as  an  acid  radical,  but 
is  precipitated  from  acid  solutions  by  H2S  as  a  sulphide, 
whether  it  is  present  as  an'  arsenious  or  arsenic  salt. 
(Special  tests  for  arsenites  and  arsenates  will  be  found  on 
page  88.) 

1.  Add  H2S  to  AsC]3  = 

Filter  and  test  solubility  of  one  portion  in  (NH4)2S 
(yellow),  and  of  second  portion  in  (NH4)2CO3. 

2.  Add  H2S  to  sol.  of  Na3AsO3  = 

A  66 


GROUP   II  —  DIVISION   B  45 

3.    Acidify  sol.  of  Na3AsO3  with  H2SO4  and  add  H2S. 

Filter  and  dry  pp.     Now  mix  a  minute  quantity  with 

Na2CO3  and   KCN,  and  heat  cautiously  in  bulb 

tube.     Black  ring  formed  on  tube  is  metallic  As. 

Complete  and  balance  the  following,  underlining   all 
precipitates  : 

AsCl3  +  H2S  = 

+  3(NH4)2C08=(NH4)8As08 

+  (NH4)2S2=(NH4)2As2S5 


+  3H0 


H2S 


QUESTIONS 


1.  What  is  the  solubility  of  As2S3  in  (NH4)2S? 

2.  In  (NH4)2CO3? 

3.  With  a  knowledge  of  the  solubilities  of  the  sulphides  of  As,  Sn, 
and  Sb,  state  how  the  sulphides  of  As  may  be  separated  from  the 
other  sulphides  of  this  group. 

4.  Give  a  symbol  for  an  arsenate. 

5.  For  an  arsenite. 

6.  On  which  side  of  a  symbol  is  the  acid  radical,  and  on  which 
side  is  the  basic  radical? 


7.  In  what  forms  is  arsenic  found  in  nature? 

8.  What  is  the  "  arsenic  "  sold  in  drug  stores  ? 

9.  What  is  white  arsenic? 

10.  What  are  some  of  its  uses  ? 

11.  What  is  Paris  green  ? 

12.  What  is  Scheele's  green  ? 

13.  What  is  the  Marsh  test  for  As? 

14.  What  are  some  of  the  dangers  of  As  in  fabrics,  wearing  ap- 
parel, and  wall  paper? 

15.  What  is  the  antidote  for  acute  arsenical  poisoning? 


46  BASIC   ANALYSIS 

Analysis.    Gr.  II,  Div.  B 

To  the  (NH4)2S  (yellow)  solution  formed  by  the  sepa- 
ration of  Gr.  II,  B,  from  Gr.  II,  A,  add  HC1.  Reject 
filtrate.  A  yellow  precipitate  may  show  the  presence  of 
Sn,  Sb,  and  As  (besides  Sz).  Do  not  mistake  the  deposit 
of  S  for  this  group. 

Wash  precipitate  twice  with  cold  H2O  and  add  cold 
(NH4)2CO3.  The  filtrate  contains  As2S3  and  As2S5  in 
solution.  The  residue  is  SnS2  and  Sb2S6.  Wash  with 
H2O,  and  add  a  few  particles  of  KC1O3  and  cone.  HC1. 
Divide  the  solution  (which  contains  SnCl4  and  SbCl5) 
into  A  and  B.  To  A  add  a  small  iron  nail  and  warm 
gently  for  some  time.  Filter,  and  to  the  filtrate  add 
HgCl2.  A  white  precipitate  of  Hg2012  shows  the  pres- 
ence of  Sn.  Pour  B  into  evaporating  dish,  dilute  with 
H2O,  and  put  in  a  small  battery  of  strips  of  Pt  foil  and 
Zn  in  contact.  Use  enough  Zn  so  that  it  will  not  be 
entirely  dissolved,  and  allow  the  battery  to  remain  until 
effervescence  of  H  ceases.  The  Sb  will  give  a  black 
deposit  on  the  Pt  foil.  If  Sn  was  not  found  in  A,  the  Pt 
foil  may  be  washed  in  warm  H2O  and  HC1,  the  wash 
water  filtered,  and  HgCl2  added  to  the  filtrate.  White 
precipitate  of  Hg2Cl2  proves  the  presence  of  Sn. 

The  black  stain  of  Sb  on  the  Pt  foil  may  be  dissolved  in 
IINO3  and  H2C4H4O6,  and  H2S  passed  through  the  solution, 
when  a  precipitate  of  Sb2S3  confirms  the  presence  of  Sb. 

To  the  (NH4)2CO3  solution  of  As2S3  and  As2S5  add 
HC1.  Yellow  precipitate  of  As2S3  and  As2S6  indicates 
As.  To  confirm  its  presence,  dry  the  precipitate,  mix 
with  equal  parts  of  Na2CO3  and  KCN,  and  heat  cautiously 
in  bulb  tube,  when  the  formation  of  metallic  mirror  or  ring 
of  As  on  upper  part  of  tube  proves  the  presence  of  As. 


GROUP  II  — DIVISION    B 


47 


TABULATION,  GR.  II,  DIV.  B 


Solution  contains  Sn,  Sb,  and  As  in  (NH4)2S  (yellow)  solution. 

Add  HC1. 


Pp.     (Sjc)        SnS      SnSa      Sb2S3      Sb2S5      As2S3 
Wash  twice  with  cold  H20  and  add  (NH4)2C03. 


Fil. 
reject 


Pp.  SnS2,  Sb2S5.  Wash,  add  KC103 
and  cone.  HC1.  Divide  the  solution 
into  A  and  B.  To  A  add  small  iron 
nail  and  warm  gently.  Filter,  and  to 
the  filtrate  add  HgCl2.  Reject  pp. 


W.  pp.     Hg2Cl2,     Sn  pres. 

Dilute  B  with  H20,  and  add  battery 

of  Pt  foil  and  Zn.     Black  stain  on 

Pt  foil,    Sb  pres. 

Wash  the  Pt  foil  carefully  with  warm 

H20  and  HOI,  filter,  and  add  HgCl2 

to  filtrate. 

W.  pp.     Hg2Cl2,     Sn  pres. 


Fil.  =  As2S3  and  As2S5  in 
solution.     Add 
HC1. 


Pp.   yellow  As2S3  and 
As2S5  (S#),    As  pres. 
Confirm  by  drying  pp.,  mixing 
with  Na2C03  and  KCN,  and 
heating  in  bulb  tube.    Arsenic 
mirror  on  upper  part  of  tube, 
As  pres. 


Notes  and  Suggestions 

The  precipitation  of  S,  on  addition  of  HC1,  must  not 
be  mistaken  for  this  group.  Sulphur  will  precipitate, 
white,  when  HC1  is  added  to  (NH4)2S.  This  difficulty 
can  be  overcome  in  part  by  using  small  quantities  of 
(NH4)2S.  When  heating  solution  A  with  an  iron  nail, 
a  precipitate  may  be  due  to  carbon  from  the  iron,  or 
metallic  Sb  from  the  reducing  action  of  nascent  H,  or 
particles  of  undissolved  iron.  In  the  case  of  the  battery 


48  BASIC   ANALYSIS 

action  in  solution  B,  if  enough  Zn  is  used  to  neutralize  all 
acid  and  the  action  is  carried  to  completion,  most  of  the  Sn 
will  be  deposited  with  Sb  on  the  Pt  foil.  The  Sn  may  be 
dissolved  off  with  HC1  and  warm  H2O  as  SnCl2.  Sb  is 
undissolved.  This  test  for  Sn  serves  as  a  check  on  the 
preceding  test.  The  (NH4)2CO3  should  not  contain 
much  NH4OH,  as  its  presence  will  dissolve  traces  of  SnS 
and  Sb2S3,  and  thus  make  necessary  the  confirmatory  test 
for  As,  with  Na2CO8  and  KCN. 

QUESTIONS 

1.  How  is  this  group  originally  precipitated? 

2.  Give  symbols  and  colors  of  the  precipitates  produced  by  the 
general  reagent  for  this  group. 

3.  How  is  this  group  separated  from  Div.  A? 

4.  Why  boil  with  an  iron  nail? 

5.  What  is  the  confirmatory  test  for  As? 

6.  What  is  the  test  for  Sn  ? 

7.  How  do  you  separate  As  from  Sn  ? 

8.  SbfromCu? 

GROUP  III -IRON  GROUP 

II  VI  VI  VI 

(Fe),     Fe2,     A12,     Cr2 

Precipitated  as  hydroxides  by  NH4OH  in  presence  of 
NH4C1. 

Preliminary  Experiments 

II  VI 

Fe,     Fe2  —  Iron.     Ferrous  and  Ferric  Compounds 

1.    Dissolve  a  very  small   piece  of   FeSO4,  free  from 
white  coating,  in  hot  water.     Divide  the  solution  into  A 


GROUP  III  49 

and  B.     Dilute  A  with  hot  H2O,  divide  into  three  por- 
tions, and  quickly  add  : 

a.  Potassic  ferrocyanide     = 

b.  Potassic  ferricyanide      = 

c.  Potassic  sulphocyanide  = 

Boil  B  with  HNO3.  Dilute  with  H2O,  divide  into 
three  parts,  and  add  : 

a.  Potassic  ferrocyanide     = 

b.  Potassic  ferricyanide      = 

c.  Potassic  sulphocyanide  = 
Name  a  test  for  ferrous  iron. 

Describe  two  tests  for  ferric  iron. 

2.  Dissolve  a  piece  of  FeSO4  in  hot  H2O  and  divide 
into  A  and  B.  Dilute  A  with  H2O,  divide  into  two  parts, 
and  add  : 

a.  NH4OH  = 

b.  NH4C1  +  NH4OH  = 

Oxidize  B  to  the  ferric  state  with  HNO3,  dilute  with 
H2O,  divide  into  two  parts,  and  add  : 

a.    NH4OH  = 

b. 


Filter  and  test  solubility  of  precipitate  in  HC1. 
3.    To  Fe2Cl6  or  any  other  soluble  ferric  salt  add  : 
(NH4)2S  =  FeS  + 


50  •        BASIC   ANALYSIS 

There  are  two  sets  of  iron  compounds,  ferrous  and 
ferric.  In  the  ferrous  compounds,  the  single  atom  Fe  is 
bivalent,  and  in  the  ferric,  the  double  atom  Fe2  is  sextiva- 
lent. 

Cl  /Cl 

Ferrous  chloride.  Fe-Cl 


n.     Ferric  chloride. 
/Cl 

Fe^-Cl 
\C1 

Ferrous  compounds  are  converted  to  ferric  by  oxida- 
tion, as  with  HNO3,  acid  reducing  agents  reverse  the 
change. 

The  simplest  form  of  the  reaction  for  converting  a 
ferrous  to  a  ferric  salt  would  be 

2  FeCl2  +  2  HCl-f  O  =  Fe2Cl6  +  H2O, 
or          2  FeSO4  +  H2SO4  +  O  =  Fe2(SO4)3  +  H2O. 

The  O  may  be  supplied  by  HNO3  or  any  other  oxi- 
dizer.  A  ferric  salt  may  be  converted  to  a  ferrous  salt 
by  the  use  of  nascent  hydrogen. 

Fe2Cl6  +  Zn  +  2  HC1  =  2  FeCl2  +  ZnCl2  +  2  HC1 ; 
or,  a  simpler  form, 

Fe2Cl6  +  H2  =  2  FeCl2  4-  2  HC1. 

The  HC1  dissolves  the  Zn,  forming  ZnCl2,  and  setting 
free  hydrogen.  This  nascent  H  removes  C12  from  FeaCl6, 
forming  HC1. 


GROUP  III  51 

Complete  and   balance  the    following,   underlining  all 


FeS04+(NH4)2S  = 

3  FeSO4  +  2  K8Fe(CN)6  =  Fe8(Fe(CN)6)2  +  3  K2SO4 
Fe2(S04)3+(NH4)2S  = 
Fe2(SO4)3  +  NH4OH  = 

-  Fe2(S04)3  +  6  KCNS  =  Fe2(CNS)6  +  3  K2SO4 
2  Fe2(S04)8+3  K4Fe(CN)6=(Fe2)2(Fe(C,N)6)8  +  6  K2S04 

QUESTIONS 

1.  What  is  the  behavior  of  the  iron  solutions  (both  -ous  and  -ic) 
with  NH4OH  ? 

2.  With  NH4OH  in  presence  of  NH4C1? 

3.  Do  you  see  a  reason  why  (since  NH4C1  must  be  added  to  this 
group)  Fe  must  first  be  oxidized  to  Fe2  ? 


4.  What  is  green  vitriol  ? 

5.  What  is  water  of  crystallization  ? 

6.  What  is  Turnbull's  blue  ? 

7.  What  is  Prussian  blue  ? 

8.  What  is  "  writing  fluid  "  ? 

9.  Why  does  "  writing  fluid  "  turn  black  on  exposure  to  the  air  ? 

10.  What  is  cast  iron  ? 

11.  Pig  iron? 

12.  Wrought  iron  ? 

13.  Steel? 

14.  Where  and  in  what  forms  is  iron  found  in  nature  ? 

15.  What  are  some  of  the  physical  properties  of  steel  ? 

16.  Of  wrought  iron  ? 

17.  Of  cast  iron? 


52  BASIC   ANALYSIS 

VI 

A12  —  Aluminum 

To  a  solution  of  A12(SO4)3,  or  a  solution  of  alum,  add  : 

1.  NH4OH  = 

Filter  and  test  solubility  of  precipitate  in  HC1. 

2.  NH4C1  +  NH4OH  = 

3.  NaOH  in  excess  = 

a.  Upon  addition  of  NaOH,  A12O6H6  is  formed,  and, 

with  an  excess  of  NaOH,  the  hydroxide  dissolves, 
forming  sodic  aluminate  Na6O6Al2.  In  this  case, 
the  A12O6H6  acts  as  an  acid,  allowing  its  H  to  be 
replaced  by  the  basic  radical  Na. 

b.  Add  NH4C1  to  the  solution  in  (3  a)  and  heat  = 

4.  (NH4)2S  =  A1206H6  + 

Complete  and  balance  the  following,  underlining  all 
precipitates  : 

A12(S04)3+NH4OH  = 

A12(S04)8  +  NaOH  = 

A1206H6  +  NaOH  =  Na6O6Al2  + 

Na606Al2+NH4Cl  = 

A12(S04)3+  3(NH4)2S  +  6  H20  =  A12O6H6 

+  3(NH4)2SO4  +  3H2S 
(Problem.     Make  a  solution  of  A12C16  from  alum.) 

QUESTIONS 

1.  Does  NH4C1  affect  the  precipitation  of  A12O6H6  by  N H4OH  ? 

2.  What  form  of  A12  is  precipitated  by  (NH4)2S? 

3.  What  is  the  effect  of  NH4C1  on  Na6O6Al2? 

4.  What  is  the  solubility  of  A12O6H6  in  NaOH  ? 


GROUP  III  53 

5.  In  what  forms  does  A12  occur  in  nature? 

6.  What  are  some  of  its  uses  and  physical  properties  ? 

7.  What  is  alum? 

8.  For  what  is  A12O6H6  extensively  used  in  the  arts? 

9.  How  are  porcelain  and  earthenware  made  ? 

VI 

Cr2  —  Chromium 

To  a  solution  of  Cr2Cl6,  Cr2(NO3)6,  or  chrome  alum,  add  : 
1.    NH4OH  = 

Filter  and  test  solubility  of  precipitate  in  HC1. 
2. 
3. 

4.    Pb(C2H302)2  = 

To  solution  of  Na2CrO4  add  Pb(C2H3O2)2= 
To  solution  of  Cr2(NO3)6  add  NH4OH  = 

Filter,  wash  pp.     Make  hole  in  filter,  and  wash  into 
beaker  with  NaOH.     Add  a  few  drops  of  H2O2, 
and  boil.     If  sol.  is  not  perfectly  clear,  filter,  notice 
color  of  filtrate,  which  should  be  yellow  from  for- 
mation of  Na2CrO4,  and  add  Pb(C2H3O2)2. 
To  solution  of  Cr2(SO4)3  add  (NH4)2S=Cr2O6H6  + 
(Problem.     Starting  with  chrome  alum,  make  a  solu- 
tion of  Cr2Cl6  and  Cr2(NO3)6.) 

Complete  and  balance  the  following,  underlining  all 
precipitates  : 
Cr2Cl6  +  NH4OH  = 
Cr2Cl6  +  NH4C1  +  NH4OH  = 
Cr2Cl6  +  NaOH  = 

Cra(NO8)6  +  Pb(C2H3O2)2  =  no  change.     Why  ? 
Pb(C2H302)2  +  Na2Cr04  = 
Cr2(S04)3  -}-  3(NH4)2S  +  6  H2O  =  Cr2O6H6+  3(NH4)2SO4 


3H2S 


IR.  QUAL.  ANAL.  —  4 


54  BASIC   ANALYSIS 

PbCrO4  "chrome  yellow,"  is  the  most  desirable  form 
in  which  to  precipitate  chromium  in  order  to  detect  it. 
Cr2  acts  both  as  an  acid  and  as  a  basic  radical.  When  H2S 
has  been  added  in  the  preceding  group,  Cr2  compounds, 
if  present,  are  reduced  to  the  basic  form,  and  Cr2  is  pre- 
cipitated as  a  base  in  the  course  of  analysis  of  Gr.  III. 
In  the  presence  of  NaOH,  Cr2  is  easily  oxidized  to  the 
acid  form  by  H2O2,  when  it  is  readily  precipitated  by 
Pb(C2H3O2)2,  as  PbCrO4. 

QUESTIONS 

1.  What  is  the  solubility  of  Cr2O6H6  in  HC1? 

2.  In  NH4OH? 

3.  In  NaOH? 

4.  In  NaOH  combined  with  H2O2? 

5.  Does  the  presence  of  NH4C1  affect  its  precipitation  as  a  hydrate? 


6.  How  does  Cr2  occur  in  nature  ? 

7.  What  is  chrome  yellow,  and  for  what  used  ? 

8.  What  is  chrome  alum,  and  for  what  used? 

Analysis.    Gr.  Ill 

Test  the  original  solution  for  Fe  and  Fe2,  with  potass ic 
ferricyanide  and  potassic  sulphocyanide  (pages  48,  49).  If 
iron  is  present,  and  H2S  has  been  added  to  remove  Gr.  II, 
the  iron  will  be  in  the  ferrous  state,  even  if  it  was  present 
only  in  the  ferric  state  in  the  original  solution.  It 
must  be  oxidized  to  the  ferric  state  by  boiling  with  a 
very  little  HNO3.  To  the  nitrate  from  Gr.  II,  or  the 
solution  found  not  to  contain  Grs.  I,  II,  add  consider- 
able NH4C1,  and  NH4OH  in  excess.  The  filtrate  con- 
tains Grs.  IV- VI,  and  is  set  aside.  The  precipitate  is 
Fe2O6H6,  Cr2O6H6,  and  A12O6H6.  Make  hole  in  filter, 


GROUP  III 


55 


and  wash  through  with  NaOH  into  beaker.  (If  neces- 
sary, transfer  the  precipitate  from  the  filter  to  the  beaker 
with  spatula.)  Boil  and  filter.  The  precipitate  contains 
Fe2O6H6  and  Cr2O6H6.  The  filtrate  is  Na6O6Al2.  Warm 
with  NH4C1,  and  allow  to  stand  some  time,  when  a  white 
flocculent  precipitate  of  A12O6H6  indicates  the  presence 
of  A12.  The  precipitate  of  Fe2  and  Cr2  is  washed  through 
the  filter  with  NaOH  as  before,  and  boiled  with  a  few  c.c. 
of  H2O2.  The  precipitate  is  Fe2O6H6,  and  may  be  dis- 
solved in  cone.  HC1  and  submitted  to  the  iron  tests.  If 
Cr2  is  present,  the  filtrate  will  be  yellow.  Acidify  the 
filtrate  with  HC2H3O2,  and  add  Pb(C2H3O2)2,  when  a 
yellow  precipitate  of  PbCrO4  confirms  the  presence  of  Cr2. 

TABULATION,  GR.  Ill 

*  Solution  contains  Grs.  III-VI. 
Add  NH4C1  and  NH4OH  in  excess. 

i 


Pp.     Fe206H6               Cr206H6               A1206H6 
Wash  through  paper  with  NaOH  and  boil. 

Fil.  = 
Grs.  IV,  V,  and  VI 

1 

Pp.     Fe206H6               0206H6 
Wash  through  paper  with  NaOH,  add  a  few 
c.c.  of  H202  and  boil. 

Fil.  Na606Al2 
Warm  with 
NH4C1.  Allow  to 
stand  some  time. 
White  pp. 
A1206H6, 
AL  pres. 

Pp.  Fe206H6.     Dissolve 
in  cone.  HC1  and  apply 
the  iron  tests. 
Test  original  solution  for 
Fe  and  Fe2  (pages  48,  49). 

Fil.  Na2Cr04,  yellow. 
Acidify  with  HC2H302 
and  add  Pb(C2H302)2. 

1 

Yellow  pp.  PbO04, 
Cr2  pres. 

*  If  Fe  is  present,  it  must  be  oxidized  by  boiling  with  a  very  little 
HNOS. 


56 


BASIC   ANALYSIS 


An  Alternative  Method  of  Analysis  for  Gr.  Ill 

Precipitate  as  in  first  method.  Wash,  dry,  and  fuse  on 
Pt  foil  with  KNO3  and  Na2CO3.  Boil  fused  mass  in  H2O 
and  filter.  The  precipitate  is  Fe2O3,  brown.  The  filtrate 
contains  Na6O6Al2  and  Na2CrO4. 

Yellow  solution  indicates  Cr2. 

Divide  the  solution  into  A  and  B. 

To  A  add  NH4C1,  warm,  and  allow  to  stand.  White 
precipitate  of  A12O6H6  indicates  A12. 

Acidify  B  with  HC2H3O2  and  add  Pb(C2H3O2)2.  Yel- 
low precipitate  of  PbCrO4  shows  Cr2  present. 

TABULATION,   GR.    Ill 

*  Solution  contains  Grs.  III-VI.     Add  NH4C1,  NH4OH  in  excess. 


Pp. 

Wash 

Fe20 
,dry, 

}H6 
and 

fuse  on 

Pt 

A1206H6 
foil  with 

KN03 

Cr206H6 

and  Na2C03. 

Fil. 

Grs. 

IV-VI 

Pp.  Fe203,  brown. 
Test  original  solu- 
tion for  Fe  and 
Fe2  (pages  48,  49). 


Fil.  Na606Al2  Na2Cr04 

Divide  solution  into  A  and  B. 
To  A  add  NH4C1  and  warm.     White  pp.  of 

A1206H6,    A12  pres. 
To  B  acidified  with  HC2H302  add  Pb(C2H302)2 

Yellow  pp.  of  PbCr04,  Cr2  pres. 


Notes  and  Suggestions 

Addition  of  NH4C1  prevents  the  precipitation  of  mem- 
bers of  Gr.  IV  and  Mg  of  Gr.  V  as  hydroxides  and  aids 
the  precipitation  of  A12O6H6  and  O2O6H6  on  addition  of 


*  If  Fe  is  present,  it  must  be  oxidized  to  Fe2  by  boiling  with  a  very 
little  HNO3. 


GROUP  IV  57 

NH4OH.  The  original  solution  must  be  tested  to  deter- 
mine in  what  form  the  iron  was  present.  If  H2S  was 
added  to  remove  Gr.  II,  any  Fe2  present  will  have  been 
reduced  to  Fe,  therefore  Fe  alone  will  be  found  on  begin- 
ning the  analysis  of  Gr.  III.  FeO2H2  is  soluble  in  pres- 
ence of  NH4C1  and  Fe2O6H6  is  not,  therefore  Fe  must  be 
oxidized.  Care  must  be  taken  not  to  carry  the  oxidation 
far  enough  to  oxidize  manganous  to  manganic  compounds, 
as  we  should  then  precipitate  Mn  with  Gr.  III.  H2O2  in 
presence  of  an  alkali  is  used  to  oxidize  Cr2  from  the  basic 
to  the  acid  state. 

QUESTIONS 

1.  What  is  the  general  reagent  for  Gr.  III? 

2.  Give  the  symbols  and  colors  of  the  precipitates  formed  by  the 
group  reagent. 

3.  What  is  the  use  of  H2O2?    NH4C1?    Why  boil  with  HNO3  ? 
*  4.   How  separate  A12  from  Cr2  ? 

5.  How  separate  Cr2  from  Fe2  ? 

6.  Give  symbols  which  illustrate  Cr2  behaving  as  an  acid  radical. 

7.  As  a  basic  radical. 

GROUP  IV— COBALT  GROUP 

ii         ii          ii         ii 
Co,     Ni,     Mn,     Zn 

Precipitated  as  sulphides  in  alkaline  solution  by  (NH4)2S. 

Preliminary  Experiments 

ii 
Co  —  Cobalt.     Cobaltous  Compounds 

To  a  solution  of  Co(NO3)2  add : 

1.  NH4OH  = 

2.  NH4OH  in  excess  = 

3.  NH4C1  and  NH4OH  = 


58  BASIC   ANALYSIS 

4.  (NH4)2S  = 

a.  Filter.     Make  a  colorless  bead   of  Na2H4O7  on  Pt 

wire  in   blowpipe  flame,  dip  in  precipitate,  and 
heat  in  the  oxidizing  flame. 

b.  Test  the  solubility  of  the  remaining  pp.  in  HC1. 

5.  NaOH  = 

Complete   and   balance  the  following,   underlining  all 
precipitates : 

Co(NO3)2+NH4OH  = 

Co(N03)2+(NH4)2S  = 
Co(NO3)2  +  NaOH 

QUESTIONS 

1.  What  is  the  solubility  of  the  hydroxide  of  cobalt  in  NII4O1I V 

2.  Jn  NH4ClandNH4OH? 

3.  What  is  the  solubility  of  CoS  in  HC1? 


4.  How  does  Co  occur  in  nature  ? 

5.  What  are  some  of  its  uses  ? 

ii 
Ni  —  Nickel.     Nickelous  Compounds 

To  a  solution  of  Ni(NO8)2  or  NiSO4  add : 

1.  NH4OH  = 

2.  NH4OH  in  excess  = 

3.  NH4C1  +  NH4OH  = 

4.  (NH4)2S  = 

a.  Filter  and  test  precipitate  with  borax  bead  as  in  the 

case  of  Co. 

b.  Test  the  solubility  of  the  remaining  precipitate  in 

HC1. 

5.  NaOH  = 


GROUP  IV  59 

Complete  and  balance  the  following,   underlining  all 

precipitates  : 

NiS04  +  NH4OH 


4  +  (NH4)2S 
Ni(N03)2  +  (NH4)2S  = 
NiS04  +  NaOH 

QUESTIONS 

1.  What  is  the  solubility  of  MO2H2  in  NH4OH  ? 

2.  In  NH4OH  and  NH4C1? 

3.  InNaOH? 

4.  What  is  the  solubility  of  NiS  in  HC1? 


5.  Where  and  in  what  forms  is  Ni  found  in  nature? 

6.  What  are  its  physical  properties  ? 

7.  What  are  some  of  its  uses  ? 

it 
Mn  —  Manganese.     Manganous  Compounds 

To  a  solution  of  MnSO4  or  MnCl2  add  : 
1.    NH4OH  = 


2. 

3.  (NH4)2S  = 

a.  Filter,  make  bead,  on  Pt  wire,  of  KNO3  +  Na2CO3, 

dip  in  the  precipitate,  and  heat  in  the  blowpipe 
flame. 

b.  Test  solubility  of  the  remaining  precipitate  in  HC1. 

4.  NaOH  = 

a.  Filter  and  test  with  bead  of  KNO3  +  Na2CO3. 

b.  Test  solubility  of  remaining  precipitate  in  HC1. 


60  BASIC   ANALYSIS 

Complete  and   balance  the  following,  underlining   all 
precipitates  : 

MnS04  +  NH4OH  = 


MnS04  +  NaOH  = 
Mn02H2  +  HC1  = 
MnS  +  HC1 

QUESTIONS 

1.  What  is  the  solubility  of  MnO2H2  in  NH4OH? 

2.  InNH4ClandNH4OH? 

3.  In  NaOH? 

4.  What  is  the  solubility  of  MnS  in  HC1? 


5.  In  what  forms  does  Mn  occur  in  nature? 

6.  What  is  black  oxide  of  manganese  ? 

7.  What  is  potassic  permanganate  and  for  what  used? 

8.  Add  a  solution  of  potassic  permanganate  to  a  solution  of  FeSO4 
acidified  with  H2SO4.     Explain  fully  what  happens. 

Note  that  Mn,  like  Cr?,  acts  both  as  an  acid  and  as 

a  basic  radical. 

ii 
Zn  —  Zinc 

To  a  solution  of  ZnSO4,  ZnCl2  or  Zn(N03)2  add  : 

1.  NH4OH  = 

2.  NH4C1  +  NH4OH  = 

3.  NaOH  cautiously  = 

4.  NaOH  in  slight  excess  =  Na2O2Zn  -f 
Compare  with  A12. 

5.  (NH4)2S  = 

Filter  and  test  solubility  of  precipitate  in  HC1. 
Make  ZnS  and  test  its  solubility  in  HC2H3O2. 
To  ZnSO4  add  H2S  = 


GROUP  IV  61 

Complete  and  balance  the  following,  underlining  all 
precipitates : 

ZnS04  +  NH4OH  = 

ZnSO4  +  NaOH     = 
ZnO2H2  +  NaOH  =  Na2O2Zn + 
ZnS04  +  (NH4)2S  = 
ZnS04  +  H2S 

QUESTIONS 

1.  What  is  the  solubility  of  ZnO2H2  in  NH4OH? 

2.  InNH4ClandNH4OH? 

3.  InNaOH? 

4.  What  is  the  solubility  of  ZnS  in  HC1? 

5.  InHC2H3O2? 

6.  Where  and  in  what  forms  does  Zn  occur  in  nature? 

7.  How  is  it  obtained  from  its  ore  ? 

8.  Give  some  of  the  physical  properties  of  Zn. 

9.  What  are  some  of  its  uses? 

10.  What  is  zinc  white  and  for  what  used? 

11.  What  is  white  vitriol  ? 

12.  Tell  what  you  can  of  the  use  of  Zn  in  battery  cells. 

13.  When  a  strip  of  Zn  is  nailed  with  iron  nails  and  exposed  to 
the  air,  why  does  the  Zn  soon  dissolve  around  the  nails  ? 

14.  What  is  galvanized  iron  ? 

Analysis.     Gr.  IV 

To  the  filtrate  from  the  precipitate  of  Gr.  Ill,  or  solu- 
tion found  not  to  contain  Grs.  I-III,  heated  to  boiling, 
add  (NH4)2S  and  keep  warm  for  some  time.  The  filtrate 
contains  Grs,  V,  VI  and  is  set  aside.  The  precipitate 
is'  CoS,  NiS,  MnS,  and  ZnS.  Wash  in  hot  H2O,  allow 
to  cool,  and  add  HC1  on  filter.  Pass  solution  through 


62  BASIC   ANALYSIS 

two  or  three  times.  The  filtrate  contains  MriCl2  and 
ZnCl2.  The  residue  is  CoS  and  NiS.  Test  residue  with 
borax  bead  in  outer  blowpipe  flame.  A  blue  bead  shows 
Co,  and  a  brown  bead  shows  Ni.  If  both  are  present,  the 
borax  bead  will  be  blue  from  the  Co,  and  the  Ni  will  be 
obscured.  To  identify  Ni  in  presence  of  Co,  dissolve 
precipitate  in  aqua  regia,  evaporate  nearly  to  dryness  to 
expel  acid,  add  NaOH  in  excess,  and  filter.  Dissolve  the 
hydroxides  in  a  little  concentrated  KCN  solution,  and 
to  this  add  NaOH  and  bromine  water.  On  boiling,  Ni, 
if  present,  is  precipitated  as  Ni2O6H6.  Co  remains  in 
solution. 

(An  Alternative  Method.  To  identify  Ni  in  presence  of 
Co,  dissolve  the  sulphides  of  Co  and  Ni  in  aqua  regia, 
evaporate  nearly  to  dryness  to  expel  acid,  add  tartaric 
acid  and  then  NaOH  in  excess.  Boil  and  pass  H2S.  A 
black  precipitate  is  CoS,  which  may  be  tested  with  borax 
bead.  The  filtrate  will  be  a  deep  brown  or  black  if  Ni 
is  present.  Test  the  solution  with  borax  bead,  which 
will  become  brown  if  Ni  is  present.) 

To  the  HC1  filtrate  containing  MnCl2  and  ZnCl2  add 
NaOH  in  excess.  The  precipitate  is  Mn()2lI2,  white, 
turning  brown  on  exposure  to  the  air.  Make  a  bead  of 
KNO3  and  Na2CO3,  dip  in  the  precipitate  and  heat  in 
blowpipe  flame.  The  formation  of  a  green  bead  of 
Na2MnO4  confirms  the  presence  of  Mn. 

The  filtrate  containing  Na2O2Zn  is  acidified  with 
HC2H3O2,  and  H2S  is  added.  A  white  precipitate  of 
ZnS  indicates  the  presence  of  Zn.  To  confirm  the  pres- 
ence of  Zn  add  cone.  HC1,  when  ZnS,  if  present,  will 
be  dissolved,  but  S  in  suspension  will  not  dissolve.  A 
partial  solution,  on  addition  of  cone.  HC1,  also  indicates 
ZnS. 


GROUP  IV 


63 


TABULATION,  GR.  IV 


Sol.  contains  Grs.  IV- VI.     Heat  and  add  (NH4)2S. 


Pp.    CoS  NiS  MnS  ZnS        Fil.  =  Grs.  V,  VI. 

Wash  with  hot  H.,0  and  add  HC1  on  cold  filter. 


Pp.    CoS                MS 
Test  with  Bx.  bead  ;  blue  indi- 
cates Co  pres.;  brown  indicates 
Ni.     If  Co  is  pres.,  dissolve  pp. 
in  aqua  regia.     Expel  acid  and 
add  NaOH  in  excess. 

Fil.  MnCl2         ZnCl2 
Add  NaOH  in  excess. 

Pp.  Mn02H2. 

Test  with 
bead  of 
KN03  and 
Na2C03. 
Green 
Na.2Mn04, 
Mn  pres. 

Fil  Na202Zn 
Acidify  with  HC2H302 
and  add  H2S. 

i 

Pp.  Co02H2            Ni02H2 
Dissolve  in  cone.  KCN  solution. 
Add  NaOH  and  Br2+H20.  Boil. 

W.  pp.  ZnS,  Zn  pres. 
To  distinguish  from 
S,  add  cone.  HC1  and 
see  if  it  dissolves. 

Pp.  Ni206H6, 
black, 
Ni  pres. 

Fil.  Na6Co2(CN)12 

Notes  and  Suggestions 

Use  as  little  acid  as  will  do  the  work,  thus  avoiding 
the  use  of  large  quantities  of  alkali  for  neutralization,  with 
the  result  of  making  the  solution  too  dilute.  If  the  solu- 
tion has  become  too  dilute,  it  should  be  concentrated  by 
evaporation. 

NiS  is  somewhat  soluble  in  excess  of  (NH4)2S,  there- 
fore the  filtrate  from  this  group  may  contain  NiS,  shown 
by  black  or  brown  color.  But  NiS  may  be  precipitated 
from  this  filtrate  by  boiling  with  a  few  drops  of  HC1. 


64  BASIC   ANALYSIS 

QUESTIONS 

1.  What  is  the  group  reagent? 

2.  Give  the  symbols  and  colors  of  all  precipitates  produced  by  the 
group  reagent. 

3.  If  the   precipitate  with   (NH4)2S  should  not  be  black,  what 
inference  ? 

4.  How  separate  Co  and  Ni  from  Mn  and  Zn  ? 

5.  Mn  from  Zn? 

6.  Co  from  A12? 

GROUP  V  — BARIUM  GROUP 

ii      ii       ii        ii 
Ba,  Sr,  Ca,  Mg 

With  the  exception  of  Mg,  precipitated  as  carbonates 
from  alkaline  solutions  by  (NH4)2CO3  in  presence  of 
NH4C1. 

Preliminary  Experiments 

ii 
Ba  —  Barium 

To  any  soluble  Ba  salt  add : 

1.  NH4OH  = 

2.  (NH4)2C03  = 

a.  Filter  and  test  solubility  of  portion  of  pp.  in  HC1. 

b.  Test  solubility  of  remainder  in  HC2H3O2. 

3.  NH4C1+(NH4)2C03  = 

4.  CaS04  = 

5.  H2S04  = 

6.  K2Cr04  = 

7.  Na2HP04  = 

8.  (NH4)2C204  = 


GROUP  V  65 

Complete  and  balance  the   following,  underlining   all 
precipitates : 

BaCl2  +  NH4OH  = 

BaCl2  +  (NH4)2CO3  = 

BaCl2  +  (NH4)2C03  +  NH4C1  = 

BaCl2  +  CaSO4  = 

BaCl2  +  H2S04  = 

BaCl2  +  K2CrO4  = 

BaCl2+(NH4)2C204  = 

BaCl2  +  Na2HP04  = 

BaCO3  +  HC2H3O2  = 

Ba(C2H302)2  +  CaS04  = 

ii 
Sr  —  Strontium 

To  any  soluble  Sr  salt  add  : 

1.  NH4OH  = 

2.  (NH4)2C03  = 

a.  Filter  and  test  solubility  of  portion  of  pp.  in  HC1. 

b.  Test  solubility  of  remainder  in  HC2H3O2. 

3.  NH4C1+(NH4)2C03  = 

4.  CaSO4  heat  and  allow  to  stand  = 

5.  H2S04  = 

6.  K2CrO4  = 

7.  Na2HP04  = 
8. 


66  BASIC    ANALYSIS 

Complete  and  balance  the  following,   underlining   all 
precipitates : 

Sr(N08)a  +  NH4OH  = 

Sr(N03)2+(NH4)2C03  = 
Sr(N03)2  4-  NH4C1  +  (NH4)2CO3  = 
Sr(N03)2  +  CaS04  = 
Sr(NO8)2  +  H2SO4  = 
Sr(N03)2+K2Cr04  = 
Sr(N03)2+Na2HP04== 
Sr(N03)2-f  (NH4)2C204  = 
SrC03  +  HC2H302  = 
Sr(C2H302)2  +  CaS04  = 

ii 
Ca  —  Calcium 

To  any  soluble  Ca  salt  add : 

1.  NH4OH  = 

2.  NH4C1  +  (NH4)2CO3  = 

3.  (NH4)2C03  = 

a.  Filter  and  test  solubility  of  portion  of  pp.  in  HC1. 

b.  Test  solubilit}'  of  remainder  in  HC2H3O2. 

4.  CaSO4  and  heat  = 

5.  H2S04  = 

6.  K2Cr04  = 

7.  Na2HPO4  = 

8.  (NH4)2C204  = 

Filter  and  test  solubility  in  HC1. 


GROUP  V  67 

Complete    and  balance  the  following,   underlining   all 
precipitates  : 

CaCl2  +  NH4OH  = 

CaCla+(NH4)2C08  = 

CaCl2  +  NH4C1  +  ( NH4)2CO3  = 

CaCl2  +  CaSO4  = 

CaCl2  +  H2SO4  = 

CaCl2  +  K2CrO4  = 

CaCl2  +  Na2HP04  = 

CaCl2+(NH4)2C204  = 

CaCOg  +  HC2H302  = 

a 
Mg  —  Magnesium 

To  any  soluble  Mg  salt  add : 

1.  NH4OH  = 

2.  NH4C1  +  NH4OH  = 

3.  (NH4)2C03  = 

4.  NH4C1+(NH4)2C03  = 

5.  CaSO4  = 

6.  H2SO4  = 

7.  K2CrO4  = 

8.  NH4OH  +  Na2HPO4  = 

9.  (NH4)2C204  = 
10.  BaO2H2  = 

Complete   and   balance  the  following,  underlining  all 
precipitates  : 

MgCl2  +  NH4OH  = 

MgCl2+(NH4)2C03  = 

MgCl2  +NH4C1  +(NH4)2CO3  =  Solution 

MgCl,  +NH4OH  +  Na2HP04  =  MgNH4PO4  + 

MgCl2+(NH4)2C204  = 

MgCl2  +  BaO2H2  = 


68  BASIC   ANALYSIS 


QUESTIONS 

1.  What  is  the  effect  of  NH4OH  on  the  members  of  this  group? 

2.  What  is  the  effect  of  NH4OH  in  presence  of  NH4C1  ? 

3.  What  is  the  effect  of  (NH4)2CO3  on  members  of  this  group  ? 

4.  What  is  the  effect  of  (NH4)2CO3  in  the  presence  of  NH4C1? 

5.  What  is  the  effect  of  CaSO4  on  each  member  ? 

6.  H2S04? 

7.  K2CrO4? 

8.  (NH4)2C204? 

9.  Na2HPO4? 

10.  What  is  the  solubility  of  the  carbonates  of  this  group  in  HC1  V 

11.  InHC2H302? 

12.  How  may  Mg  be  separated  from  the  other  members  of  this 
group  ? 


13.  In  what  forms  does  Ba  occur  in  nature  ? 

14.  Give  one  use  for  Ba(NO3)2. 

15.  OneforBaSO4. 

16.  In  what  forms  does  Sr  occur  in  nature  ? 

17.  Give  one  use  for  Sr(NO3)2. 

18.  In  what  forms  does  Ca  occur  in  nature  ? 

19.  What  is  marble  ? 

20.  Limestone? 

21.  Chalk? 

22.  Stalactite? 

23.  Stalagmite? 

24.  Quicklime? 

25.  Slaked  lime? 

26.  Limewater? 

27.  Gypsum? 

28.  Plaster  of  Paris? 

29.  What  is  the  reaction  tor  making  quicklime  from  limestone  ? 

30.  What  is  mortar  ? 

31.  Can  you  point  out  the  changes  that  take  place  when  mortar 
hardens  ? 


GROUP  V  69 

Analysis.    Gr.  V 

The  filtrate  from  the  Gr.  IV  precipitate  may  be  concen- 
trated by  evaporation.  If  the  solution  is  not  colorless,  boil 
with  a  few  drops  of  HC1  and  filter.  To  the  concentrated 
colorless  solution  heated  to  boiling,  add  NH4C1  if  not 
already  present,  NH4OH  until  alkaline,  and  (NH4)2CO3. 
The  filtrate  is  Mg  and  Gr.  VI,  and  is  set  aside.  The  pre- 
cipitate is  BaCO3,  SrCOg,  and  CaCO3.  This  precipitate 
is  washed  with  hot  H2O  and  dissolved  by  pouring  a  few 
c.c.  HC2H3O2  orrthe  filter,  and  passing  through  two  or 
three  times.  Divide  the  solution  into  two  unequal  parts. 
To  the  smaller  portion  of  the  solution  add  CaSO4.  An 
immediate  precipitate  indicates  the  presence  of  Ba.  Ca 
and  Sr  may  be  present.  A  tardy  precipitate  shows  Ba 
absent,  Sr  present  —  Ca  may  be.  No  precipitate,  on  boil- 
ing and  standing,  proves  the  absence  of  Ba  and  Sr  and 
the  presence  of  Ca. 

If  Ba  is  present,  it  is  precipitated  by  adding  K2CrO4 
to  the  larger  portion  of  the  solution,  and  is  filtered  out. 
To  the  filtrate  is  added  NH4OH  until  alkaline,  and  then 
(NH4)2CO3.  The  precipitate  may  contain  SrCO3  and 
CaCO3.  This  precipitate  is  washed  with  hot  H2O  and 
dissolved  in  HC2H3O2.  To  a  small  portion  of  the  solu- 
tion add  CaSO4.  A  tardy  precipitate,  showing  only  after 
heating  and  standing,  is  SrSO4,  and  indicates  the  presence 
of  Sr.  Ca  may  be  present.  No  precipitate  shows  Sr 
absent  and  that  the  precipitate  with  (NH4)2CO3  must 
have  been  CaCO3.  If  Sr  is  present,  it  must  be  precipi- 
tated in  the  remaining  solution  with  H2SO4,  and  filtered 
out.  The  filtrate  is  made  alkaline  with  NH4OH  and 
(NH4)2C2O4  is  added.  A  white  precipitate  of  CaC2O4 
indicates  the  presence  of  Ca. 

IR.  QUAL.   ANAL.  — 5 


70  BASIC   ANALYSIS 

TABULATION,    GR. 


Solution  contains  Grs.  V,  VI.      Heat  to  boiling  and 

add  NH4C1,  NH4OH,  and  (NH4)2C03. 
f 


Pp.     BaC03  SrC03  CaC03       Fil.  =  Mg  and  Gr.  VI. 

Wash,  dissolve  in  HC2H302. 

Divide  sol.  into  A  and  B.     To  A  add  CaS04.* 

Immediate  pp.,  Ba  pres.  (Sr,  Ca?)  Tardy  pp.,  Baabs.  Sr  pres.  (Ca?) 
No  pp.,  Ba  and  Sr  a  Us.     Ca  pres. 
If  Ba  is  present,  to  B  add  K,Cr04. 


Pp.  BaCr04, 

yellow. 

Reject 


Fil.  Sr(C2H302),          Ca(C2H30,)2 
Warm,  add  NH4OH  and  (NH4),CO;!. 


Pp.  SrC03  CaC03  Wash, 

dissolve  in  HC2H302.     Divide  sol.  into  A  and  B.     To  A  add  CaSO,.t 

Tardy  pp.,  Sr  pres.     (Ca?)     No  pp.,  Sr  abs.     Ca  pres. 
If  Sr  is  present,  to  B  add  H2S04. 


Pp.  SrS04,  white. 
Reject. 


Fil.  Ca(C2H302)2.     Add  NH4OH  and  (NH4)XA 


Pp.  white  CaC204,     Ca  pres. 


Notes  and  Suggestions 

NH4C1  keeps  Mg  in  solution  so  that  it  is  found  with 
Gr.  VI. 

It  is  not  necessary  to  add  NH4OH  and  NH4C1,  if  the 

*t  When  Ba  and  Sr  on  the  first  addition  of  CaSO4  (*),  or  Sr  on  the 
second  addition  of  CaS04  (t),  are  proved  absent,  the  presence  of  Ca 
should  be  confirmed  by  adding  NH4OH  and  (NH4)oC204  to  HC2H3O, 
solution  B. 


GROUP  VI  71 

solution  is  a  filtrate  from  Grs.  Ill  and  IV,  as  they  are 
in  that  case  already  present. 

The  solution  must  not  be  acid  when  adding  (NH4)2CO3. 

The  carbonates  are  washed  to  free  them  from  the  alka- 
lies NH4OH  and  (NH4)2CO3  and  to  avoid  the  use  of 
much  HC2H3O2. 

To  distinguish  between  Ba  and  Sr,  use  is  made  of  the 
fact  that  Sr  precipitates  as  the  sulphate  slowly  or  in  dilute 
solutions  only  with  heat  and  standing. 

Ba  is  removed  by  K2CrO4. 

Sr  is  removed  as  SrSO4  by  H2SO4. 

All  the  Ba,  Sr,  and  Ca  must  be  removed  before  testing 
for  Mg  (see  pages  72,  73),  as  they  are  all  precipitated  by 
Na2HP04. 

QUESTIONS 

1.  What  is  the  general  reagent  for  Gr.  V? 

2.  Give  names  and  colors  of  all  precipitates  formed  by  it. 

3.  Why  must  Ba  be  removed  before  testing  for  Sr? 

4.  Why  remove  Sr  before  testing  for  Ca? 

5.  Suppose  that  the  group  precipitate  is  formed  and  that,  on  the 
addition  of  CaSO4,  no  precipitate  is  shown  ;  why  do  you  infer  the 
presence  of  Ca? 

6.  How  confirm  the  presence  of  Ca? 

GROUP  VI  -SODIUM  GROUP 

Na,    K,    Li,    NH4 

This  group  is  not  precipitated  by  any  single  reagent, 
and  its  members  must  be  detected  by  special  tests. 

Clean  a  Pt  wire  by  dipping  in  cone.  HOI  and  burning 
in  Bunsen  burner  flame. 

Examine  the  colorless  Bunsen  burner  flame  with  a  spec- 
troscope. 


72  BASIC   ANALYSIS 

Moisten  the  Pt  wire,  dip  in  a  salt  of  Na,  ignite  in  flame, 
and  notice  the  color.  Ignite  before  the  spectroscope  and 
draw  diagram  of  the  spectrum,  noting  particularly  the 
location  of  the  yellow  line. 

Dip  the  clean  wire  into  a  salt  of  K,  ignite  in  colorless 
flame,  and  note  the  color.  If  Na  is  on  the  same  wire,  the 
color  will  be  obscured,  but  may  be  observed  through 
cobalt  glass.  Ignite  before  the  spectroscope.  Draw 
diagram  of  spectrum,  noting  particularly  the  position  of 
the  narrow  red  lines. 

Dip  the  clean  Pt  wire  into  a  salt  of  Li.  Note  the  color 
on  ignition  in  colorless  flame.  Ignite  before  the  spectro- 
scope, and  draw  diagram  of  the  spectrum,  noting  position 
of  red  lines. 

Rub  NH4C1  and  CaO2H2  together  in  palm  of  hand. 
Note  odor.  To  a  solution  of  an  NH4  salt  add  CaO2H2  or 
NaOH.  Heat  gently.  Note  odor  and  action  of  gas  on 
moist  red  litmus  paper.  Be  careful  not  to  bring  the 
litmus  paper  in  contact  with  the  reagent  used,  as  it  is  an 
alkali. 

Analysis  of  Mg  and  Gr.  VI 

The  filtrate  from  the  precipitate  of  Gr.  V  will  contain 
Mg  as  well  as  Gr.  VI.  Divide  the  solution  into  two 
parts.  To  the  first  portion  add  Na2HPO4;  a  white  pre- 
cipitate of  MgNH4PO4  indicates  the  presence  of  Mg.  If 
Mg  is  absent,  evaporate  second  portion  to  dryness,  ignite 
to  drive  off  NH4,  and  test  in  spectroscope  for  Na,  K,  and 
Li.  If  Mg  is  present,  evaporate  second  portion  to  dry- 
ness,  ignite  to  drive  off  NH4  salts  (as  MgO2H2  will  not  pre- 
cipitate in  presence  of  NH4  salts),  redissolve  in  H2O,  heat, 
and  add  BaO2H2.  The  precipitate  is  MgO2H2.  Reject 
this  precipitate,  as  the  presence  of  Mg  in  the  spectrum 


MG   AND   GROUP  VI 


73 


interferes  with  the  detection  of  Na,  K,  and  Li.  The 
nitrate  contains  BaCl2,  which  must  be  removed,  as  Ba 
lines  in  the  spectrum  interfere  with  the  detection  of 
Gr.  VI.  Therefore  add  H2SO4.  The  precipitate  BaSO4 
is  rejected.  The  nitrate  is  now  evaporated  to  dryness, 
ignited,  and  tested  before  the  spectroscope  for  Gr.  VI. 

As  N  H4  salts  have  been  added  in  the  course  of  the  analy- 
sis, the  original  solution  must  be  tested  with  CaO2H2  or 
NaOH  for  NH4. 

TABULATION,  MG   AND   GR,  VI 

Solution  contains  Mg,  Na,  K,  Li,  and  NH4. 

Divide  the  solution  into  A  and  B.     To  A  add  Na,HP04. 


Pp.  MgNH4P04,  white,     Mg  pres. 

If  Mg  is  absent,  evaporate  B  to  dryness,  ignite,  and  test  in  spectro- 
scope for  Na,  K,  and  Li. 

If  Mg  is  present,  evaporate  B,  ignite,  and  redissolve  in  H20. 
Heat  and  add 


Pp.  Mg02H2.  Reject. 

Fil.  BaCl2  and  Gr.  VI. 
Add  H2S04. 

1 

Pp.  BaS04 
Reject. 

Fil.  evaporate  to  dryness,  ignite, 
and  test  with  spectroscope  for 
Na,  K,  and  Li. 
Test   the   original   solution   for 
NH4  with  CaOoHo. 

QUESTIONS 


1.  What  is  the  chief  source  of  Na  in  nature? 

2.  What  is  common  salt,  and  where  found? 


74  BASIC   ANALYSIS 

3.  What  is  Glauber's  salt? 

4.  Washing  soda  ? 

5.  Cooking  soda? 

6.  Sal  soda? 

7.  Bicarbonate  of  soda  ? 

8.  Caustic  soda? 

9.  What  is  the  Le  Blanc  process? 

10.  What  is  Chile  saltpeter? 

11.  How  is  hard  soap  made  ? 

12.  What  is  the  chief  source  of  K  in  nature  ? 

13.  What  is  potash  ? 

14.  Pearlash? 

15.  Caustic  potash  ? 

16.  Saltpeter  or  niter? 

17.  Prussiate  of  potash  ? 

18.  Saleratus? 

19.  How  is  gunpowder  made? 

20.  How  is  soft  soap  made? 

21.  What  is  lithia  water? 

22.  What  is  salatnmoniac,  and  for  what  used? 

23.  What  is  the  source  of  the  ammonia  compounds  used  in  com- 
merce ? 

24.  Referring  to  the  table  of  solubilities  shown  on  the  last  page 
of  this,  book,  note  the  solubilities  of  all  the  common  salts  of  Na,  K, 
and  NH4. 

Unknown  solutions  containing  any  of  the  bases  may 
now  be  analyzed.  If  the  solution  is  to  be  examined  for 
all  the  bases,  first  test  small  portions  of  the  original  solu- 
tion for  Fe,  Fe2,  and  NH4.  Then,  with  a  small  portion 
of  the  solution,  make  a  preliminary  test  with  the  group 
reagents  to  determine  what  groups  may  be  present  (see 
page  75).  Knowledge  may  be  gained  in  this  way  which 
will  greatly  shorten  the  work  of  analysis. 

On  the  four  pages  next  after  75  all  the  previous  tables 
of  analysis  are  repeated,  for  convenience,  in  the  form  of 
one  complete  table. 


ALL   GROUPS 


75 


PQ 

O 

O 


RATION 
AGENTS 


m 


& 


O 


h 


>V 

J  w 


o  ^ 


A 
PH 


P_i 


II 


o 


d    * 
i    nd 


PQ  OT  6 


Q 


N 


q  q  q 

^  Q  <1 


*  i  S  h 


PQ 


OQ 


d, 
PH 


76 


BASIC  ANALYSIS 


Solution  contains  Gi 


Pp.  Hg,Cl2       AgCl       PbCl2 

Fil.  =  Grs.  II-VL       Heat  tc 

Wash  with  hot  H,0  until  Pb  is 

all  dissolved.          j 

Pp.  HgS         PbS         Bi2S3 

Pp.  Hg.,CI2    Fil-  f" 

Agoi  A<M  y 

\\'ash  several  times  by  decanta 

WicK    tvifh                           X\' 

Pp.  HgS         PbS         Bi.,S3 

wasn  \\iuii    "      —  /  \  — 

NH.OH.      pP/*Me  PbS04, 

\\"ash  into  beaker  with  HNO 

IKk 

—  T~ 

*ro  pres. 

1                                                 \ 

Pp.  HgS, 

black.    Dis- 

Fil. Pb(N03), 
Partially  ev;ip 

Pp.  Hg2  NH2C1,    Fil.  AgCl 
black,                     in  sol. 

Hg.,  pres.      Add  HNO.. 

solve  in  cone. 
HC1  and 

iPp.  white  is 

1 

Pp.  white 

KCICX,  and 

PbS04  ;      / 

AgCl, 

add  SnCl,. 

\pb  pres{ 

Ag  pres. 

1 

ft).  BioA, 

....  . 

>>  lute  or  gray 
pp.  Hg.Cl* 

white,  j 

Hg  pres. 

Or, 

Bi  pres. 

Confirui  by 

Add  Cu  foil. 

dissolving  in 

Silver-colored 

2  or  \p  drops 

( 

deposit  on  foil 

of  ccfoc.  HC1 

.shows 

and  allowing 

Hg  pres. 

to  arori  into 
lar$e  volume 

of  k20. 

White  cloud 

of'BiOCl,, 

Bi  pres. 

ALL  GROUPS 


77 


Add  HC1  to  Cold  Solution. 


ind  add  H2S. 

~r 


CdS       (SnS.    SnS2    Sb2S3    Sb2S5    As2S3    As2S5) 
ish  through  filter  with  (NH4)2S  and  warm. 


Fil.  =  Grs.  III-VI 
(see  page  78). 


CdS 

to  boiling. 


Fil.  =  Gr.  II,  Div.  B,  Sn,  Sb,  and  As. 
Add  HC1. 


Cu(N03)2    Cd(N03)2 
a  few  drops  H2S04. 

Pp.    (S#)    SnS    SnS2  '  Sb 

As2S3     As2S5 

,83    Sb2S5        Filtrate, 
reject. 

| 

Wash  twice  with  cold  H2( 

)  and  add 

)8)3  Cu(N03)2  Cd(N03)2 

(NH4)2C03. 

^H  in  slight  excess 

1 

Pp.    SnS2    Sb2S5 

Fil.  =  As  in  solution. 

Cu  pres. 

t   te*t  a  portion  of  sol 

Wash,    add    KC103    and 
cone.    HC1.      Divide   sol. 

Add  HC1. 

~r 

H30,  and  K4Fe(CN)6; 
t,     Cu  pres. 

into  A  and  JS.     To  A  add 
small  iron  nail  and  warm 
gently.       Filter    and    to 

Pp.  yellow  As2S3  and 
As2S5   (S4 

abs.  add  H2S  to 

filtrate  add  HgCl2.    Reject 

As  pres. 

Confirm  by  mixing 

sol.             | 

pp.                   1 

dry  pp.  with  Na2C03 

7  CdS,     Cd  pres. 

Pp.  w.  Hg2C]2,  Sn  pres. 

and  KCN  and 

present,  add  KCN 
ntil  blue  color  just 
,  and  then  H2S. 

B.  Dilute  with  H20  and 
add  battery  of  Pt  and  Zn. 
Black  stain  on  Pt, 

heating  in  bulb  tube= 
As  mirror  on  upper 
part  of  tube, 
A«  tares 

1 

Sb  pres. 

f  CdS,     Cd  pres. 

Wash  Pt  foil  with  warm 
H20  and  HC1,  filter,  and 
add  HgCl2. 
W.  pp.  HgoCL,,  Sn  pres. 

-• 

78 


BASIC   ANALYSIS 


I 


I 


02  ^ 

I 


111 

^  2 

-M    o 


Q 


ff  a  5  a 


II 


3     * 


0 


-  - 


'•     ISL 

oJ5 1  -i  te  I 


O  '3 


'     + 


o 
O 


-1 


£-1 


l 


?,& 

Q  ^a 

I 


ft -5 

f: 


8| 

eS    K 


tJD  .-*- 

'i  '5 

2  c 

*3  — 

.5  1 


>FJ  -^ 


ALL   GROUPS 


79 


M  I 


fcJO*^     05  .^4  ""*     CD 

J£f 5*1 

£-a.a§Bi 


°o* 


. 

M  -  <2  B 

'^18-9 

tz;  H  -43  O 


i"° 
"i 

p 


w 


,0 


a:^ 

£3 

co  ^r 


" 


IS 


O 


02  ^ 


(C 

0 


" 


'.2 


a- 

PH 


PART   IV  — SOLIDS 


THE   SYSTEMATIC  EXAMINATION  OF  SOLIDS 

IN  this  analysis  not  only  will  the  bases  be  identified, 
but  also  the  acids  combined  with  them,  and,  therefore, 
the  composition  of  the  salt.  Thus,  if  the  analysis  shows 
the  presence  of  Ba  and  HC1,  the  substance  is  identified  as 
BaCl2. 

Preliminary  Examination 

If  the  substance  is  neither  a  metal  nor  an  alloy,  it  must 
be  powdered  in  a  porcelain  mortar,  and  small  portions 
used  for  each  test.  (For  metals  and  alloys,  see  page  86.) 

Do  not  spend  too  much  time  on  this  preliminary  exami- 
nation, nor  rely  too  much  on  results  obtained  from  it  until 
your  experience  in  this  particular  work  has  been  somewhat 
extended. 

I 
Heat  Small  Portion  of  Substance  in  Bulb  Tube. 

1.  Turns  black,  or  carbonizes,  has  burnt  odor,  —  organic 
substance. 

2.  Gives  H2O;    determine  whether   alkaline   or   acid. 
May  be    H2O  of   crystallization,   or  water   mechanically 
held. 

80 


PRELIMINARY  EXAMINATION 


81 


3. 

Hot 

Yellow 
Red  to  black 
Yellowish  red 
Orange  yellow 

4. 


Color 


Cold 
White 


—  Zn  salts 


Brownish  red  —  Fe  or  Fe2  salts 
Yellow  -Pb  salts 

Pale  yellow       -  Bi  salts 


Gases  with  Odor  or  Color 


Odor 

Color 

Burning  matches 

Colorless 

—  S02 

Pungent 

Colorless 

-NH4 

Suffocating 

Green 

-Cl 

Stifling 

Brownish 

red—  Br 

Acrid 

Violet 

-I 

Peach  blossom 

Colorless 

-CN 

Rotten  eggs 

Colorless 

-H9S 

Garlic 

Colorless 

-AsH 

Odorless 

Colorless 

—  C09 

Sulphites 
NH4  salts 
Chlorides 
Bromides 
Iodides 
Cyanides 
Sulphides 

AsH3    As  compounds 
Carbonates 

Drop  of  limewater  on  glass  rod  rendered  turbid  —  CO2. 


5. 


Sublimates 


White  may  indicate  compounds  of  NH4,  As,  Hg,  or  Sb. 
Yellow,  when  cold  —  S     Free  S,  or  sulphides. 
Black  —  I     Iodides. 

II 

Heat  on  Charcoal  in  Blowpipe  Flame. 

SO2  given  off  —  S  and  sulphides 

Decrepitation  -  Water 

Deflagration  -  Nitrates  or  chlorates 

Melts  and  runs  into  charcoal  —  Bases  of  Grs.  V,  VI 


82  SOLIDS 

To  any  residue  on  the    charcoal   add    Co(NO3)2   and 
heat  again  in  oxidizing  flame. 

Blue  indicates  A12 

Green         indicates  Zn 
Rose  color  indicates  Mg 

III 

Heat  on  Charcoal  with  Na2GO8  in  Reducing  Flame. 
Metallic  globules  or  beads  indicate  Cu. 

Metallic  globules  or  beads,  malleable,  indicate  Ag,  Pb, 
or  Sn. 

Metallic  globules  or  beads,  brittle,  indicate  Sb  or  Hi. 

Dark-colored   powder,   magnetic,   indicates  Fe,    Fe2<    (V 
or  Ni. 

IV 

Fuse  into  Borax  Bead  and  Heat  in  Oxidizing  Flame, 
then  in  Reducing  Flame. 

Oxidizing  flame  Reducing  flame 

Blue  Blue  -Co 

Brown  Gray  or  colorless  —  Ni 

Blue  Red  or  colorless  — Cu 

Green  (yellowish)  Green  — Cr2 

Colorless  or  yellow  Bottle  green  -  Fe  or  Fe2 

Amethyst  Colorless  -Mn 


PRELIMINARY   EXAMINATION  83 


Flame  Colorations 

Moisten  Clean  Pt  Wire  in  HC1  and  ignite  in  Bunsen 
Burner  Flame. 

Violet  indicates  K 

Yellow  indicates  Na 

Carmine  red  indicates  Li 
Yellowish  red  indicates  Ca 
Bright  red  indicates  Sr 
Green  indicates  Ba 

Blue  to  green  indicates  Cu 

VI 

Ignite  before  the  Spectroscope  and  examine  for 
Characteristic  Lines. 

VII 

Treatment  with  Cone.  H2SO4 

This  is  the  most  important  single  preliminary  test,  as 
it  will  show  the  presence  of  the  volatile  acids,  and  some 
of  them  may  be  positively  identified  by  color  and  odor. 

Place  a  small  portion  of  solid  in  test  tube,  cover  with  a 
few  drops  of  cone.  H2SO4,  and  heat  cautiously  (see  page 
84,  3).  Observe  color  of  any  gases  given  off  and  note 
odor  with  care.  To  examine  the  odor  safely,  hold  test  tube 
at  slight  distance  and  fan  fumes  toward  the  nose  so  that 
they  will  be  diluted  with  air,  and  gradually  bring  test  tube 
nearer.  If  any  particular  acid  is  indicated  at  this  point, 
that  acid  may  be  further  identified  by  applying  the  appro- 
priate acid  test,*  provided  the  solid  dissolves  readily  in 


H20. 


*  See  Acid  Analysis,  Part  V. 


84  SOLIDS 

* 

1.  Turns  black,  gives  odor  of  burnt  sugar,  H2C4H4O6 

-  Tartrates 

2.  Odor  of  vinegar,  HC2H3O2  —  Acetates 

3.  Yellowish  green  vapor,  suffocating  and  acrid,  C12O3 

—  Chlorates 

Must  not  be  heated,  as  chlorates  are  highly  explo- 
sive with  H2SO4. 

4.  Effervescence,  odor  of  HC1  —  Chlorides 
Bring  near  the  test  tube  glass  rod  moistened  with 

NH4OH.  Heavy  white  clouds  of  NH4C1  con- 
firm presence  of  HC1. 

5.  Effervescence  with  odor  of   burnt  matches,  SO2. 
Bring  paper  moistened  with  Hg2(NO3)2  near  test 

tube.  Paper  turning  black  confirms  presence  of 
SO2  —  Sulphites 

6.  Effervescence,  odor  of  rotten  eggs,  H2S 

—  Sulphides 

7.  Effervescence,  odor  acrid,  corrodes  test  tube,  HF 

—  Fluorides 

8.  Effervescence  sudden,  no  odor,  CO2  —  Carbonates 
Decant  CO2  carefully  into  test  tube  one  fourth  full 

of  limewater  and  shake  the  limewater.  Tur- 
bidity due  to  the  formation  of  CaCO3  confirms 
the  presence  of  CO2. 

9.  Violet  vapor,  acrid  odor,  HI  and  I       -Iodides 

10.  Reddish  brown  vapor,  suffocating  odor,  NO2 

-  Nitrates 

11.  Brownish  red  vapor,  stifling  odor,  HBr  and  Br 

-  Bromides 

12.  Odor  of  peach  blossoms,  CN  (deadly  poison) 

—  Cyanides 


STUDY  OF  SOLUBILITY  85 

The  Solid  must  now  be  Dissolved 

I  —  Water  Solution 

a.  Place  a  very  small  quantity  in  test  tube  and  treat 
first  with  cold  water  and  then  with  boiling  water.     If  it 
is   entirely   soluble,    dissolve    a   larger   portion.      Use   a 
portion   of   the   solution  and  perform  the  basic  analysis 
(Part  III,  pages  28-73).     Follow  with  the  acid  analysis 
(Part  V,  pages  88-94). 

b.  The  substance  may  be  partially  soluble  in  water.    This 
can  be  determined  by  evaporating  a  few  drops  of  nitrate 
on  Pt  foil,  when  a  residue  will  show  that  a  portion  has 
dissolved.      Make  this  partial  solution  of  a  considerable 
quantity,  reserving  the  residue  for  treatment  by  II,  and 
perform  the  basic  and  acid  analyses  with  this  solution. 

II  —  Acid  Solution 

The  substance  insoluble  in  H2O,  or  the  residue  from  the 
substance  partially  dissolved  in  H2O,  is  treated  with  dil. 
HC1,  then  Avith  cone.  HC1,  first  cold,  then  boiling.  Treat 
in  the  same  way  with  dil.  and  then  cone.  HNO3,  and  finally 
with  aqua  regia.  After  each  treatment,  a  few  drops  of  the 
filtrate  should  be  evaporated  on  Pt  foil  to  see  if  any  has 
dissolved.  Any  solution  produced  by  any  one  of  these 
methods  must  be  separately  analyzed  for  bases  and  acids. 

If  the  substance  has  not  dissolved,  or  if  a  residue  is  left 
undissolved,  it  should  be  treated  by  III. 

Ill  —  Solution  by  Means  of  Fusion 

The  original  substance  or  the  residue  from  II,  insoluble 
in  water  or  acid,  is  fused  on  Pt  foil,  or  in  a  Pt  crucible 
with  KNO3  and  Na2CO3.  Boil  the  residue  with  water 
until  it  is  disintegrated. 


86  SOLIDS 

BOIL   WITH    H20 

I 


Pp.  contains  bases 
as  carbonates.    Treat 
with  cone.  HC1  to 
dissolve.     Evaporate 
part  of  acid  and 
analyze  in  the  usual 
way  for  bases. 


Fil.    contains   acid    radicals.      Treat   a  small 
portion  with  cone.  HC1. 


W.  pp.  washed  with  hot  H20  and  dried  feels 
"gritty,"  —  Si02,  showing  silicates.  If  Si02 
is  pres.,  this  filtrate  is  analyzed  for  acids.  If 
Si02  is  abs.,  the  remaining  H20  fil.  is  analyzed 
for  acids. 


If  the  Substance  is  a  Metal  or  Alloy 

Boil  with  one  part  cone.  HNO3  in  three  parts  of  H2O.  If 
the  substance  dissolves  with  no  residue,  dilute  with  II2O, 
and  proceed  with  the  basic  analysis.  A  few  particles  of 
carbon  deposited  from  iron  and  a  few  other  metals  may  be 
disregarded.  If  a  white  residue  forms,  dilute  with  con- 
siderable H2O  and  boil,  as  certain  nitrates  like  Pb(NO3)2 
are  insoluble  in  cone.  HNO3,  but  soluble  in  dil.  HNO3. 
If  a  white  residue  still  remains,  it  may  contain  the  oxides 
of  Sn  and  Sb.  Filter  and  analyze  the  filtrate  for  bases. 
Dissolve  the  pp.  in  cone.  HC1,  dilute  with  H2O,  and  pro- 
ceed according  to  the  basic  analysis,  Gr.  II,  Div.  B. 

Order  of  Examination  of  Any  Solid : 

I.    Preliminary  examination. 
II.    A  study  of  the  solubility  of  the  substance. 
III.    If  any  acids  have  been  identified,  an  elimination 
from  consideration  of  any  bases  that  must  evidently  be 
absent  from  the  conditions  of  solution.     For  example,  CO2 
is  found  in   the   preliminary   examination,  and   the    sub- 
stance is  soluble  in  H2O.    Under  these  conditions,  no  bases 
can  be  present  except  those  of  Gr.  VI,  as  carbonates  of  Grs. 


SYSTEMATIC   EXAMINATION  87 

I-V  are  insoluble  in  H2O.  (See  table  of  solubilities  on 
page  100.)  Again,  HC1  is  found  in  the  preliminary 
examination  and  the  substance  is  easily  soluble  in  H2O. 
Gr.  I  cannot  be  present,  as  the  chlorides  of  this  group  are 
not  readily  soluble  in  H2O.  (See  page  100.) 

IV.  Systematic  basic  analysis,  preceded  by  a  prelimi- 
nary examination  of  a  small  portion  of  the  solution  for 
the  groups  by  use  of  group  reagents.     (See  page  75.) 
This  may  greatly  shorten  the  work  of  analysis,  as  certain 
groups  may  be  found  absent. 

V.  An    elimination    from    consideration    of    H3As03, 
H3AsO4,  and  H2CrO4,  as  As  and  Cr2  (including  Cr),  if 
present,  will  have  been  found  in  the  basi'c  analysis  (As, 
page  46,  and  Cr2,  page  55).     It  is  now  only  necessary  to 
determine  whether  the  As  is  present  in  the  -ous  or  -ic 
form,  and  whether  the  Cr2  is*  present  as  an  acid  or  as  a 
basic  radical  (page  88). 

VI.  An   elimination  from   consideration  of   any  acids 
that  are  positively  identified  by  H2SO4  in  the  preliminary 
examination  (page  83,  VII);  and  of  any  acids  that  cannot 
exist,  under  the  conditions  of  solution,  with  the  bases  pres- 
ent.    The  student  will  need  to  consider  at  this  point  prob- 
lems like  these.     In  the  basic  analysis,  Ag  or  Hg2  has  been 
found,  and  the  substance  is  soluble  in  H2O :    it  is  useless 
to  test  for   HC1,  as  AgCl  and   Hg2Cl2  are  insoluble  in 
H2O  (page  100).     Suppose  that  we  have  found  Ag,  Sr, 
and  Cu  in  a  water  solution  :    AgCl,  AgBr,  Agl,  SrSO4, 
and  CuS  are  insoluble  in  H2O  (page  100),  therefore  HC1, 
HBr,  HI,  H2SO4,  and  H2S   must  be  absent.     Or,  if  Ba  has 
been  found  in  a  water  solution,  none  of  the  acids  of  Gr.  I 
(pages  88-90)  can  be  present,  as  the  Ba  salts  of  those 
acids  are  insoluble  in  II 2O  (page  100). 

VII.  Acid  analysis  (pages  88-94). 


PART   V  — ACID   ANALYSIS 


GROUP  I -DIVISION  A 

*  H2CrO4,     H3As03,     H3AsO4,     H2SO3, 
H4Si()4,     II2C03 

The  first  three  of  these  acids  will  have  been  found  in 
the  basic  analysis  (pages  47  and  55),  as  they  are  reduced 
by  H2S  in  the  presence  of  H'Cl. 

The  presence  or  absence  of  the  last  three  acids  will  have 
been  proved  in  the  preliminary  examination  (pages  83, 
VII,  and  86). 

Special  tests  must  now  be  applied  to  determine  whether 
Cr2  is  present  in  the  acid  or  basic  form,  and  whether  the 
As  is  in  the  -ous  or  -ic  form. 

H2CrO4.  Acidify  with  HC2H3O2  and  add  Pb(G2H8O2)2. 
Yellow  precipitate  of  PbCrO4  indicates  Chromates. 

H3AsO3  and  H3AsO4.  H2S  precipitates  As  as  As2S3 
from  acid  solutions  in  both  cases.  As  in  the  -ous  form 
is  precipitated  quickly,  but  in  the  -ic  form  very  slowly. 
This  will  serve  to  distinguish  Arsenites  from  Arsenates. 

H2SO3.  Treat  with  H2SO4  or  HC1.  SO2  is  given  off 
and  may  be  recognized  by  the  characteristic  odor  of  burn- 

*  Although  some  of  these  acids  never  occur  except  in  their  salts,  the 
full  symbol  of  the  hypothetical  acid  is  here  given. 

88 


GROUP  I  89 

ing  matches  and  also  by  blackening  of  paper  moistened 
with  Hg2(NO3)2.  Zn  and  HC1  liberate  H  mixed  with 
H2S  from  solutions  of  Sulphites. 

H4SiO4.  Addition  of  HC1  separates  H4SiO4  in  the  form 
of  a  gelatinous  precipitate.  Filter,  wash,  and  dry,  when 
it  is  converted  into  SiO2  and  may  be  recognized  by  its 
gritty  feel.  Silicates. 

H2CO3.  Add  cone.  HC1.  Quick  and  energetic  effer- 
vescence of  CO2.  Pass  gas  into  limewater;  a  white  pre- 
cipitate of  CaCOg  confirms  the  presence  of  Carbonates. 

Give   the   names  of  products  formed  in  the  following 

cases  : 

Potassic  chromate  and  lead  acetate  =  ? 
Sodic  arsenite  and  hydrogen  sulphide  =  ? 
Sodic  arsenate  and  hydrogen  sulphide  =  ? 
Sodic  sulphite  and  sulphuric  acid  =  ? 
Sodic  carbonate  and  sulphuric  acid  =  ? 
Sodic  silicate  and  hydrochloric  acid  =  ? 
Silicic  acid  plus  heat  =  ? 

GROUP  I  — DIVISION  B 
H3P04,  H2SO4,  HF,  H2C4H406,  H8BO8 

*  Group  T,  Div.  A,  of  the  acids,  and  certain  bases,  must 
be  removed  before  testing  for  these  acids.     To  do  this, 
add  HC1,  and  heat.      This  removes  H2CO3  and  H2SO3, 
and  precipitates  Gr.  I  of  the  bases,  and  H4SiO4.     Filter 
(if  a  precipitate  occurs),  and  add  H2S  to  the  filtrate. 
This  treatment  precipitates  Gr.  II  of  the  bases,  including 

*  For  methods  of  removing  the  bases  more  completely  than  here  indi- 
cated, the  student  is  referred  to  Wm.  A.  Noyes's  "  Qualitative  Analysis," 
pages  62,  63. 

IR.   QUAL.   ANAL. 6 


90  ACID   ANALYSIS 

H3AsO3  and  H3AsO4.  To  the  filtrate  add  NH4OH  in 
just  sufficient  quantity  to'  render  the  solution  only 
slightly  alkaline.  This  removes  H8CrO4  as  well  as  Fe2 
and  A12.  Use  small  portions  of  the  filtrate  for  the  fol- 
lowing tests,  unless  directed  to  use  the  original  solid: 

Add  BaCl2  to  the  slightly  alkaline  solution,  free  from 
acids  of  Gr.  I,  A,  and  bases  of  Grs.  I— III.  If  no  precipi- 
tate is  formed,  all  the  members  of  Gr.  I,  Div.  B  of  acids 
are  absent. 

If  BaCl2  produces  a  precipitate  insoluble  in  HC1,  it  is 
BaSO4,  and  H2SO4  is  proved  present.  If  the  precipitate 
is  soluble  in  HC1,  H2SO4  is  absent.  In  either  case,  special 
tests  must  be  applied  for  other  members  of  the  group. 

H3PO4.  Phosphates  may  be  detected  in  water  solu- 
tions by  addition  of  NH4OH,  NH4C1,  and  MgSO4,  when  a 
white  crystalline  precipitate  of  MgNH4PO4will  be  formed 
on  standing.  In  acid  solutions  (preferably  HNO3  solu- 
tions) phosphates  may  be  detected  by  the  addition  of  a 
few  drops  of  (NH4)2MoO4  dissolved  in  HNO3.  A  yel- 
low precipitate  immediately  formed  on  warming  slightly 
shows  Phosphates. 

H2SO4.  Add  BaCl2  to  a  neutral  or  slightly  alkaline 
solution;  a  precipitate  insoluble  in  HC1  is  BaSO4,  showing 

Sulphates. 

HF.  Treat  the  original  solid  with  cone.  H28O4  in  Pb 
dish.  A  gas  evolved  that  will  etch  glass  shows  Fluorides. 

H2C4H4O6.  Treat  the  original  solid  with  cone.  H2SO4. 
Carbonization  with  odor  of  burnt  sugar  shows  the  pres- 
ence of  Tartrates. 

H3BO3.  Stir  cone.  H2SO4  into  the  original  solid  in 
porcelain  dish.  Add  alcohol  and  kindle.  An  apple- 
green  flame  shows  the  presence  of  Borates. 


GROUP  II  91 

Give  names  of  products  formed  in  the  following  cases : 

Calcic  phosphate  and  ammonic  molybdate  =  ? 
Ammonic  hydrate,  ammonic  chloride,  and  magnesic  sul- 
phate =  ? 

Sodic  sulphate  and  baric  chloride  =  ? 
Calcic  fluoride  and  baric  chloride  =? 
Calcic  fluoride  and  sulphuric  acid  =  ? 
Potassic  tartrate  and  baric  chloride  =  ? 
Sodic  borate  and  sulphuric  acid  =  ? 

GROUP  II 

Precipitated  by  AgNO8  in  HNO3  solution. 
HC1,    HBr,    HI,    H2S,    HCN,    H4Fe(CN)6,    H3Fe(CN)6 

H2S  and  HCN  will  have  been  proved  present  or  absent 
with  certainty  in  the  preliminary  analysis  (page  83,  VII). 
Some  indication  as  to  the  presence  of  HC1,  HBr,  and  HI 
will  also  have  been  afforded. 

A  solution  of  the  original  solid  without  removal  of  bases 
will,  in  most  cases,  be  suitable  for  the  analysis  of  this  group. 

If  the  solid  was  originally  dissolved  in  HC1,  it  is  obvious 
that  some  other  means  of  solution,  such  as  the  use  of 
HNO3,  must  be  found  before  proceeding  to  the  analysis 
of  this  group.  H2S,  if  present, 'must  be  removed.  If  it 
is  present  in  the  free  state,  it  may  be  removed  by  boiling ; 
if  in  combination,  by  precipitation  with  some  salt  which 
will  not  affect  the  other  acids  of  this  group. 

Acidify  a  portion  of  the  original  solution  of  the  solid, 
or  a  portion  from  which  H2S  has  been  removed,  with 
HNO3,  and  add  AgNO3.  The  precipitate  may  be  AgCl 
(white),  AgBr  (light  yellow),  Agl  (yellow),  AgCN 
(white),  Ag4Fe(CN)6  (white),  Ag3Fe(CN)6  (brownish 
red). 


92  ACID  ANALYSIS 

If  there  is  no  precipitate  with  AgNO3,  proceed  to 
Gr.  III.  If  a  precipitate  is  formed,  add  NH4OH.  If 
the  precipitate  dissolves,  HI  and  H4Fe(CN)6  are  absent. 

Further  investigation  must  be  carried  on  by  means  of 
special  tests. 

HC1,  HBr,  HI.  If  any  one  of  these  acids  alone  is  pres- 
ent, the  following  is  a  simple  method  of  recognizing  it : 
To  a  portion  of  the  'solution  add  MnO2  and  cone.  H2SO4. 
Apply  heat  very  gently. 

Evolution  of  a  yellowish  green  gas  which  bleaches 
calico  shows  Chlorides. 

Evolution  of  brownish  red  gas  with  suffocating  odor, 
only  partially  bleaching  calico,  shows  Bromides. 

Evolution  of  violet  vapor  which  sublimes  on  the  test 
tube  shows  Iodides. 

Also  add  starch  paste  and  chlorine  water  to  a  solution 
of  the  solid.  Blue  shows  Iodides. 

For  methods  of  detecting  chlorides,  bromides,  and 
iodides  in  presence  of  one  another  the  student  is  referred 
to  more  advanced  works  on  Qualitative  Analysis. 

HCN.  On  treating  the  original  solid  with  cone.  H2SO4, 
CN  with  odor  of  peach  blossoms  is  freed.  (It  is  a  deadly 
poison  when  breathed  undiluted  with  air.)  Cyanides. 

H4Fe(CN)6.  To  a  portion  of  the  solution  add  Fe2ClG. 
A  dark  blue  precipitate  of  Prussian  blue  shows 

Ferrocyanides. 

H3Fe(CN)6.  To  a  portion  of  the  solution  add  freshly 
made  FeSO4.  A  dark  blue  precipitate  of  Turnbull's  blue 
shows  Ferricyanides. 

(AgNOg  gives  a  brownish  red  precipitate  with  hydro- 
ferricyanic  acid;  consequently  if  the  group  precipitate  with 
AgNOg  was  white,  it  need  not  be  tested  for.) 


GROUP  III  93 

H2S.  Add  cone.  HC1  to  original  solid  and  heat.  Odor 
of  rotten  eggs  shows  sulphides.  Add  aqua  regia,  and  those 
sulphides  which  are  not  decomposed  by  HC1  throw  down  S 
and  also  form  a  small  quantity  of  H2SO4.  Sulphides. 

Give  names  of  products  formed  in  the  following  cases : 

Hydrochloric  acid  and  silver  nitrate  =  ? 

Hydrobromic  acid  and  silver  nitrate  =  ? 

Hydriodic  acid  and  silver  nitrate  =  ? 

Sodic  chloride,  black  oxide  manganese,  and  sulphuric 
acid  =  ? 

Sodic  bromide,  black  oxide  manganese,  and  sulphuric 
acid  =  ? 

Sodic  iodide,  black  oxide  manganese,  and  sulphuric 
acid  =  ? 

Potassic  cyanide  and  silver  nitrate  =  ? 

Potassic  cyanide  and  sulphuric  acid  =  ? 

Hydroferrocyanic  acid  and  silver  nitrate  =  ? 

Hydroferricyanic  acid  and  silver  nitrate  =  ? 

Sodic  sulphide  and  silver  nitrate  =  ? 

GROUP  III 
HN03,         HC103,         HC2H302 

As  the  salts  of  this  group  are  all  soluble,  there  is  no 
general  group  reagent.  (See  solubilities,  page  100.) 

HNO3.  To  a  solution  of  the  original  solid  add  con- 
centrated solution  of  FeSO4  and  cone.  H2SO4,  allowing  a 
few  drops  to  run  down  the  side  of  the  inclined  test  tube. 
Brown  or  black  ring  of  NO2  shows  Nitrates. 

A  Second  Test.  —  Add  Cu  filings  to  a  solution  of  the 
original  solid,  and  then  cone.  H2SO4.  Brownish  red  fumes 
of  NO0  show  Nitrates. 


94  ACID   ANALYSIS 

HClOg.  Treat  portion  of  the  original  solid  with  cone. 
HC1.  A  yellowish  green  gas  similar  in  odor  to  Cl  shows 

Chlorates. 

This  gas  is  observed  when  Sb  and  Sn  are  dissolved  with 
KC1O3  and  cone.  HC1.  (See  page  46.)  Also,  chlorates  def- 
lagrate on  charcoal.  (See  preliminary  test,  page  81,  II.) 

HC2H3O2.  Treat  portion  of  the  original  solid  with 
cone.  H2SO4.  Odor  of  vinegar  shows  Acetates. 

Second  Test.  —  Put  a  little  of  the  solid  in  test  tube,  add 
a  little  alcohol  and  an  equal  volume  of  coric.  H2SO4. 
The  formation  of  ethyl  acetate  with  a  fragrant  and  fruity 
odor  shows  Acetates. 

Give  the  names  of  products  formed  in  the  following 
cases : 

Sodic  nitrate,  ferrous  sulphate,  and  sulphuric  acid  =  ? 
Sodic  nitrate,  copper  filings,  and  sulphuric  acid  =  ? 
Potassic  chlorate  and  hydrochloric  acid  =  ? 
Sodic  acetate  and  sulphuric  acid  =  ? 

QUESTIONS 

1.  How  do  you  prove  the  presence  of  a  chromate  ? 

2.  A  sulphite?  10.  A  chloride? 

3.  An  arsenite?  11.  A  bromide? 

4.  A  carbonate  ?  12.  An  iodide  ? 

5.  A  silicate?  13.  A  cyanide? 

6.  A  borate  ?  14.  A  sulphide  ? 

7.  A  fluoride?  15.  A  chlorate? 

8.  Atartrate?  16.  A  nitrate? 

9.  A  sulphate  ?  17.  An  acetate  ? 

18.  How  prove  the  presence  of   H2S04  in  the  presence  of  silver, 
lead,  or  mercurous  mercury? 

19.  A  chloride  in  the  presence  of  a  sulphide? 

20.  A  nitrate  in  the  presence  of  an  iodide  ? 


PART   VI  — APPENDIX 

.      PREPARATION  OF  SOLUTIONS 
Acids 

Acetic  Acid.     A  high  grade  of  commercial  acid  may  be 
used. 

Hydrochloric,  concentrated.     Use  commercial  acid. 

Hydrochloric,  dilute,  made  by  adding  one  part  of  cone, 
acid  to  four  parts  of  H2O. 

Nitric,  concentrated.     Use  commercial  acid. 

Nitric,  dilute,  made  by  adding  1  pt.  of  cone,  acid  to 
4  pts.  of  H2O. 

Sulphuric,  concentrated.     Use  commercial  acid. 

Sulphuric,  dilute,  made  by  adding  1  pt.  of  cone,  acid  to 
4  pts.  of  H2O. 

Other  Reagents 

Ammonic  Carbonate.     Dissolve  1  pt.  of  the  salt  in  4  pts. 
of  H2O  and  add  1  pt.  of  strong  ammonic  hydroxide. 

Ammonic    Chloride.     Dissolve  1  pt.   of   the   salt   (free 
from  sulphuric  acid)  in  10  pts.  of  H2O. 

Ammonic  Hydroxide.     Add  1  pt.    of   commercial   am- 
monic hydroxide  to  3  pts.   of  H2O. 

95 


96  APPENDIX 

Ammonic  Molybdate.  Dissolve  60  grams  of  the  dry  salt 
in  400  c.c.  of  NH4OH;  add  400  c.c.  of  H2O ;  then  cau- 
tiously add  500  c.c.  of  HNO3  (specific  gravity  1.4). 

Ammonic  Oxalate.  Dissolve  1  pt.  of  the  salt  in  24  pts. 
of  H20. 

Ammonic  Sulphide.  Pass  H2S  through  NH4OH  until 
it  will  give  no  precipitate  on  heating  gently  with  MgSO4. 
The  yellow  variety  will  soon  form  on  exposure  to  the  air. 

Baric  Hydroxide.     Make  a  saturated  solution  of  BaO. 

Bromine  Water.  Made  by  adding  a  few  drops  of  liquid 
bromine  to  water  in  a  flask  and  shaking  vigorously. 

Calcic  Sulphate.     Make  a  saturated  solution. 

Chlorine  Water.  Made  by  adding  cone.  HC1  to  KC1O3 
in  bottle,  then  adding  water ;  keep  stoppled  and  covered 
with  opaque  paper. 

Disodic  Phosphate.  Dissolve  1  pt.  of  the  salt  in  10  pts. 
of  H20. 

Hydrogen  Peroxide.  Use  as  bought.  Keep  in  a  cool 
place. 

Lead  Acetate.  Dissolve  1  pt.  of  the  salt  in  10  pts.  of 
H20. 

Limewater.     Make'a  saturated  solution  of  CaO2H2. 

Potassic  Chromate.  Dissolve  1  pt.  of  the  salt  in  10  pts. 
of  H20. 

Potassic  Ferricyanide.  Dissolve  1  pt.  of  the  salt  in 
10  pts.  of  H2O. 

Potassic  Ferrocyanide.  Dissolve  1  pt.  of  the  salt  in 
10  pts.  of  H2O. 

Potassic  Sulphocyanide.  Dissolve  1  pt.  of  the  salt  in 
25  pts.  of  H2O. 


PREPARATION  OF  SOLUTIONS         97 

Silver  Nitrate.  Dissolve  1  pt.  of  the  salt  in  50  pts. 
of  H20. 

Sodic  Chromate.  Dissolve  1  pt.  of  the  salt  in  10  pts. 
of  H2O. 

Sodic  Hydroxide.  Dissolve  1  pt.  of  the  salt  in  8  pts. 
of  H20. 


Solutions  to  be  kept  for  the  Purpose  of  making  Known 
and  Unknown  Mixtures 

In  nearly  all  cases,  commercial  salts  will  be  of  a  suffi- 
cient degree  of  purity,  but  it  is  well  to  have  on  hand  a 
supply  of  chemically  pure  nitrates  of  the  metals,  as  by 
making  use  of  the  nitrates  a  large  number  of  bases  may 
be  mixed  in  one  solution. 

Alum.     1  pt.  salt  in  10  pts.  of  H2O. 

Aluminic  Chloride.  Precipitate  A12O6H6  by  adding 
NH4OH  to  a  solution  of  alum.  Wash  the  precipitate 
free  from  H2SO4  and  dissolve  in  HC1. 

Aluminic  Nitrate.  Same  as  A12C16  except  that  the 
A12O6H6  is  dissolved  in  HNO3. 

Aluminic  Sulphate.  A  solution  of  alum  will  serve  the 
purpose  as  well. 

Antimonious  Chloride.  May  be  bought  in  the  form  of 
solution.  This  should  be  diluted  with  an  equal  volume 
of  water  and  cone.  HC1  added  to  dissolve  the  basic  salt 
formed. 

Arsenious  Acid.  Made  by  dissolving  "  white  arsenic  " 
in  cone.  HC1. 

Baric  Chloride.     1  pt.  salt  in  5  pts.  H2O. 

Baric  Nitrate.     1  pt,  C.  P.  salt  in  10  pts.  H2O. 


98  APPENDIX 

Bismuth  Chloride.  Dissolve  the  subnitrate  of  bismuth 
in  cone.  HC1.  Dilute  with  twice  its  vol.  of  H2O  and  add 
cone.  HC1  to  dissolve  the  oxychloride  precipitate. 

Cadmic  Chloride.     1  pt.  salt  in  10  pts.  H2O. 

Cadmic  Nitrate.     1  pt.  C.  P.  salt  in  10  pts.  H2O. 

Calcic  Chloride.     1  pt,  salt  in  5  pts.  H2O. 

Calcic  Nitrate.     1  pt.  C.  P.  salt  in  10  pts.  H2O. 

Chrome  Alum.     1  pt.  salt  in  10  pts.  H2O. 

Chromic  Chloride.  Precipitate  Cr2O6H6  from  chrome 
alum,  wash  free  from  H2SO4,  and  dissolve  in  HC1. 

Chromic  Nitrate.  Made  like  Cr2Cl6  except  that  the 
hydroxide  is  dissolved  in  HNO3. 

Chromic  Sulphate.     Use  chrome  alum  solution. 

Cobaltous  Nitrate.     1  pt.  salt  in  10  pts.  H2O. 

Cupric  Chloride.     1  pt.  salt  in  10  pts.  H2O. 

Cupric  Nitrate.     1  pt.  salt  in  10  pts.  H2O. 

Cupric  Sulphate.     1  pt.  salt  in  10  pts.  H2O. 

Ferric  Chloride.     1  pt.  salt  in  20  pts.  H2O. 

Ferric  Nitrate.     1  pt.  salt  in  20  pts.  H2O. 

Lead  Acetate.     1  pt.  salt  in  10  pts.  H2O. 

Lead  Nitrate.     1  pt.  C.  P.  salt  in  5  pts.  H2O. 

Lithic  Chloride.  Dissolve  10  grams  LiCO3  in  HNO3 
and  boil  off  CO2.  Dilute  with  water  to  500  c.c. 

Magnesic  Chloride.     1  pt.  salt  in  10  pts.  H2O. 

Magnetic  Nitrate.     1  pt.  C.  P.  salt  in  10  pts.  H2O. 

Magnesic  Sulphate.     1  pt.  salt  in  10  pts.  H2O. 

Manganous  Chloride.     1  pt.  salt  in  10  pts.  H2O. 

Manganous  Sulphate.     1  pt.  salt  in  10  pts.  H2O. 

Mercuric  Chloride.     1  pt.  salt  in  20  pts.  H2O. 


PREPARATION  OF  'SOLtiTIO&S 

Mercurous  Nitrate.  Dissolve  metallic  mercury  in  cone. 
HNO3,  using  enough  Hg  so  that  a  few  globules  will  re- 
main undissolved.  Mercurous  nitrate  will  crystallize  out. 
Make  a  saturated  solution  of  this  salt  in  H2O.  Add  a 
globule  of  mercury  to  the  solution. 

Nickelous  Nitrate.  Dissolve  1  pt.  C.  P.  salt  in  10 
pts.  H2O. 

Nickelous  Sulphate.     1  pt.  salt  in  10  pts.  H2O. 
Potassic  Nitrate.     1  pt.  C.  P.  salt  in  10  pts.  H2O. 
Silver  Nitrate.     1  pt.  salt  in  10  pts.  H2O. 
Sodic  Arsenate.     1  pt.  salt  in  10  pts.  H2O. 
Sodic  Chloride.     Saturated  solution. 

Stannous  Chloride.  May  be  purchased  in  form  of  solu- 
tion. Should  be  kept  in  the  -ous  form  by  adding  some 
granulated  tin. 

Strontic  Chloride.     1  pt.  salt  in  10  pts.  H2O. 
Strontic  Nitrate.     1  pt.  C.  P.  salt  in  10  pts.  H2O. 
Tartar  Emetic.     1  pt.  salt  in  10  pts.  H2O. 
Zinc  Chloride.     1  pt.  salt  in  10  pts.  H2O. 
Zinc  Nitrate.     1  pt.  C.  P.  salt  in  10  pts.  H2O. 
Zinc  Sulphate.     1  pt.  salt  in  10  pts.  H2O. 


100  i  ^ABLE   OF   SOLUBILITIES 


Li 

K 
X; 
Mg 

Ca.  l-HO1O1OlrHOlrHrH^lrHrHrHCOT^rHrHTj<C'l^l»OT-lrH 

Sr  1-HOlOlOlrHOlrHrHT^rH       .'    rH    CO   rH    rH    rH   rH   <N   Ol   CO   rH   ?1 

Ba  rH   Ol   01   Ol   rH   Ol   rH   rH   Ol   T*       ;T*COrHrHrHrH<NOi:OrHOl<N 

Zn  rH   <N       I   01   rH    N    rH   rH   rn    01   01   CO   •*   01   i-H   rH   01   (N   =">   rn    M    rH   M 

Mn  rH   ?1  IN   IN  rH  M   rn   rH  rH   Ol   :0   Ol   Ol   N   rH   rH  <N  IN   Ol  rH  (M  (M   T* 

Ni 
Co 

'£>       A12         rH  Ol   I  Ol  rH   .'  rH  rH   ;   [   ]   \  rH  C-1  rH  rH  CO  -N  CC  rH  <M  (>1  <N 
^Q       Cr2         rH  01   :  01  10  N  rH  10  W  01   :   ;  rH  (N  rH  rH  -O  01  IN  •*  CO  rH  rH 

•3  Fe'2 

™         Fe 

*        ±L 

rg        Sb  :  01  01   :  rt   ;   ;  ^  01   :   :   :  rn  01  ^   :  <M  ^   :  <M  M  CN  rn 

Cd 

I 

CU  rH   01   O1 

Bi 

H{J  1-HC1O1        '    rH    C-l    rH    rH    -f    i— t        '        '•»*!        'OlrHOlOl        'rHOIOIIN 

Pb  rH    C^    Ol    Ol    »O    Ol    rH    O    CO    Ol    ^f*    Ol    Ol    Ol    -^    rH    (N    Ol    Ol    CO    Ol    Ol    Ol 

Ag  I         rHOlOIOICCOIr-IMOirrMCCrH       :    CO    rH    01    01       :    •*    01    01    (N 

rH  cc  01    ;    ;    :    :    ;  01  rn  01  01    ;  ^  c-«  01  *# 
•    •    •   ••••^•jjS   *•*••« 

Jl*j|lSf«ll«3B    '  -     '-2JS5R-* 

*  .t:  *  S  = 

g  g  «  aj 

£  2  S 


STORER    AND    LINDSAY'S 

Elementary   Manual   of  Chemistry 

BY  F.  H.  STORER,  S.B.,  A.M.,  and  W.  B.  LINDSAY,  A.B.,  B.S. 

Cloth,  12mo,  453  pages.     Illustrated.     Price,  $1.20 

This  work  is  the  lineal  descendant  of  the  "  Manual  of 
Inorganic  Chemistry"  of  Eliot  and  Storer,  and  the  "  Ele- 
mentary Manual  of  Chemistry  "  of  Eliot,  Storer  and  Nichols. 
It  is  in  fact  the  last  named  book  thoroughly  revised, 
rewritten  and  enlarged  to  represent  the  present  condition 
of  chemical  knowledge  and  to  meet  the  demands  of  American 
teachers  for  a  class  book  on  Chemistry,  at  once  scientific 
in  statement  and  clear  in  method. 

The  purpose  of  the  book  is  to  facilitate  the  study  and 
teaching  of  Chemistry  by  the  experimental  and  inductive 
method.  It  presents  the  leading  facts  and  theories  of  the 
science  in  such  simple  and  concise  manner  that  they  can 
be  readily  understood  and  applied  by  the  student.  The 
book  is  equally  valuable  in  the  classroom  and  the  laboratory. 
The  instructor  will  find  in  it  the  essentials  of  chemical 
science  developed  in  easy  and  appropriate  sequence,  its 
facts  and  generalizations  expressed  accurately  and  scientifi- 
cally as  well  as  clearly,  forcibly  and  elegantly. 


"  It  is  safe  to  say  that  no  text-book 
has  exerted  so  wide  an  influence 
on  the  study  of  chemistry  in  this 
country  as  this  work,  originally 
written  by  Eliot  and  Storer.  Its 
distinguished  authors  were  leaders 
in  teaching  Chemistry  as  a  means 
of  mental  training  in  general  edu- 
cation, and  in  organizing  and  per- 
fecting a  system  of  instructing 
students  in  large  classes  by  the 
experimental  method.  As  revised 
and  improved  by  Professor  Nichols, 
it  continued  to  give  the  highest 
satisfaction  in  our  best  schools  and 
colleges.  After  the  death  of  Pro- 
fessor Nichols,  when  it  became 


necessary  to  revise  the  work  again, 
Professor  Lindsay,  of  Dickinson 
College,  was  selected  to  assist  Dr. 
Storer  in  the  work.  The  present 
edition  has  been  entirely  rewritten 
by  them,  following  throughout  the 
same  plan  and  arrangement  of  the 
previous  editions,  which  have  been 
so  highly  approved  by  a  generation 
of  scholars  and  teachers. 

"  If  a  book,  like  an  individual, 
has  a  history,  certainly  the  record 
of  this  one,  covering  a  period  of 
nearly  thirty  years,  is  of  the  highest 
and  most  honorable  character." 
— Front  The  American  Journal  of 
Science. 


Copies  of  this  book  will  be  sent  prepaid  to  any  address,  on  receipt  of  the  price^ 
by  the  Publishers  : 

American   Book  Company 

New  York  «  Cincinnati  »  Chicago 

(99) 


Laboratory    Physics 


Hammel's  Observation   Blanks  in   Physics 

By  WILLIAM  C.  A.  HAMMEL,  Professor  of  Physics  in 
Maryland  State  School.  Boards,  Quarto,  42  pages. 
Illustrated. 30  cents 

These  Observation  Blanks  are  designed  for  use  as  a 
Pupil's  Laboratory  Manual  and  Note  Book  for  the  first 
term's  work  in  the  study  of  Physics.  They  combine  in 
convenient  form  descriptions  and  illustrations  of  the  appa- 
ratus required  for  making  experiments  in  Physics,  with 
special  reference  to  the  elements  of  Air,  Liquids,  and  Heat; 
directions  for  making  the  required  apparatus  from  simple 
inexpensive  materials,  and  for  performing  the  experiments, 
etc.  The  book  is  supplied  with  blanks  for  making  drawings 
of  the  apparatus  and  for  the  pupil  to  record  what  he  has 
observed  and  inferred  concerning  the  experiment  and  the 
principle  illustrated. 

The  experiments  are  carefully  selected  in  the  light  of 
experience  and  arranged  in  logical  order.  The  treatment 
throughout  is  in  accordance  with  the  best  laboratory  practice 
of  the  day. 

Hon.  W.  T.  Harris,  U.  S.  Commissioner  of  Education, 
says  of  these  Blanks: 

<:I  have  seen  several  attempts  to  assist  the  work  of 
pupils  engaged  in  the  study  of  Physics,  but  I  have  never 
seen  anything  which  promises  to  be  of  such  practical  assist- 
ance as  Hammers  Observation  Blanks." 


Specimen   copies  of  the  above  book  will  be  sent  prepaid  to  any  address, 
on  receipt  of  the  price \  by  the  Publishers  : 

American   Book   Company 

New  York  •  Cincinnati  *  Chicago 


Burnet's  Zoology 

FOR 
HIGH     SCHOOLS    AND    ACADEMIES 

BY 

MARGARETTA  BURNET 

Teacher  of  ZoiJlogy,  Woodward  High  School,  Cincinnati,  O. 

Cloth,  12mo,  216  pages.     Illustrated.     Price,  75  cents 


This  new  text-book  on  Zoology  is  intended  for  classes 
in  High  Schools,  Academies,  and  other  Secondary  Schools. 
While  sufficiently  elementary  for  beginners  in  the  study  it  is 
full  and  comprehensive  enough  for  students  pursuing  a 
regular  course  in  the  Natural  Sciences.  It  has  been  prepared 
by  a  practical  teacher,  and  is  the  direct  result  of  school-room 
experience,  field  observation  and  laboratory  practice. 

The  design  of  the  book  is  to  give  a  good  general  knowl- 
edge of  the  subject  of  Zoology,  to  cultivate  an  interest  in 
nature  study,  and  to  encourage  the  pupil  to  observe  and  to 
compare  for  himself  and  then  to  arrange  and  classify  his 
knowledge.  Only  typical  or  principal  forms  are  described, 
and  in  their  description  only  such  technical  terms  are  used 
as  are  necessary,  and  these  are  carefully  denned. 

Each  subject  is  fully  illustrated,  the  illustrations  being 
selected  and  arranged  to  aid  the  pupil  in  understanding  the 
structure  of  each  form. 


Copies  of  Burnefs  School  Zoology  will  be  sent  prepaid  to  any  address, 
on  receipt  of  tke  price,  by  the  Publishers: 

American   Book  Company 

New  York  »  Cincinnati  »  Chicago 

(102) 


A  New  Astronomy 

BY 

DAVID  P.  TODD,  M.A.,  Ph.D. 

Professor  of  Astronomy  and  Director  of  the  Observatory,  Amherst  College. 


Cloth,  i2mo,  480  pages.     Illustrated     -      -     Price,  $1.30 


This  book  is  designed  for  classes  pursuing  the  study  in 
High  Schools,  Academies,  and  Colleges.  The  author's 
long  experience  as  a  director  in  astronomical  observatories 
and  in  teaching  the  subject  has  given  him  unusual  qualifi- 
and  advantages  for  preparing  an  ideal  text-book, 
noteworthy  feature  which  distinguishes  this  from 
jxt-books  on  Astronomy  is  the  practical  way  in 
the  subjects  treated  are  enforced  by  laboratory 
experiments  and  methods.  In  this  the  author  follows  the 
principle  that  Astronomy  is  preeminently  a  science  of 
observation  and  should  be  so  taught. 

By  placing  more  importance  on  the  physical  than  on 
the  mathematical  facts  of  Astronomy  the  author  has  made 
every  page  of  the  book  deeply  interesting  to  the  student 
and  the  general  reader.  The  treatment  of  the  planets  and 
other  heavenly  bodies  and  of  the  law  of  universal  gravita- 
tion is  unusually  full,  clear,  and  illuminative.  The  mar- 
velous discoveries  of  Astronomy  in  recent  years,  and  the 
latest  advances  in  methods  of  teaching  the  science,  are 
all  represented. 

The  illustrations  are  an  important  feature  of  the  book. 
Many  of  them  are  so  ingeniously  devised  that  they  explain 
at  a  glance  what  pages  of  mere  description  could  not  make 
clear.  ,  

Copies  of  Todd's  New  Astronomy  will  be  sent,  prepaid,  to  any  address 
on  receipt  of  the  price  by  the  Publishers  : 

American   Book   Company 
NEW  YORK  »  CINCINNATI  »  CHICAGO 

(108) 


HOME  USE 

CIRCULATION  DEPARTMENT 
MAIN  LIBRARY 


1  mnt,  . 

R  mnnth'i03"8  may  ^  renewed  by  calling  642-3405 
6-month  loans  may  be  recharged  by  bringing  books 

to  Circulation  Desk. 

Renewals  and  recharges  may  be  made  4  days  prior 
to  due  date. 

B0°  7  DAYS 


JB*JK    APR    275 


General  Library 

University  of  California 

Berkeley 


237577 


